Ford F-150 (2004-2008) :: 2005 F150 5.4L Hesitation Under Load


Jul 22, 2011

How's it going? I have a 2005 F150 with the 5.4L V8. It has 70,000 miles on it and until yesterday and has been a great truck. While driving in traffic yesterday the truck started running rough and hesitating. It through two codes - misfire cylinder 5 and misfire cylinder 6.

In response, I purchased two new coils and 8 new autolite plugs. The plug installation went smoothly and the coils all went on without incident. However, this didn't fix the problem!

The next day I found that cylinders 5, 6, 7, and 8 were all having issues. At this point I also had an "O2 stuck lean" code so I pulled the plugs and found all four brand new plugs fouled and smelling like gas and an ehaust that smelled like raw fuel. This led me to replace the O2 sensor on the drivers side. With the new O2 my lean code disappeared but I still had a rough idle.

Further troubleshooting found that injector 6 was stuck open (which presumably fouled my O2 causing it to read lean and dump fuel thus fouling all the plugs on one side). I replaced the injector and the rough idle disappeared and all seemed really well as the truck idled in my driveway.

However, as soon as I hit the road I noticed a major hesitation. The motor is also noticeably louder and has a very hard time accelerating. I'm thinking that I've plugged up my cat by dumping so much fuel in to it and the hesitation is caused by a lack of breathing - does this sound possible? How would I confirm this without replacing the cat? Anything else I should look for? I'm fairly confident I have combustion in all 8 cylinders now so I'm leaning towards intake/exhaust issues.

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Ford F-150 (2004-2008) :: 2005 - Hesitation Under Load - Combustion In All 8 Cylinders - Cat?

I have a 2005 F150 with the 5.4L V8. It has 70,000 miles on it and until yesterday and has been a great truck. While driving in traffic yesterday the truck started running rough and hesitating. It through two codes - misfire cylinder 5 and misfire cylinder 6.

In response, I purchased two new coils and 8 new autolite plugs. The plug installation went smoothly and the coils all went on without incident. However, this didn't fix the problem!

The next day I found that cylinders 5, 6, 7, and 8 were all having issues. At this point I also had an "O2 stuck lean" code so I pulled the plugs and found all four brand new plugs fouled and smelling like gas and an exhaust that smelled like raw fuel. This led me to replace the O2 sensor on the drivers side. With the new O2 my lean code disappeared but I still had a rough idle.

Further troubleshooting found that injector 6 was stuck open (which presumably fouled my O2 causing it to read lean and dump fuel thus fouling all the plugs on one side). I replaced the injector and the rough idle disappeared and all seemed really well as the truck idled in my driveway.

However, as soon as I hit the road I noticed a major hesitation. The motor is also noticeably louder and has a very hard time accelerating. I'm thinking that I've plugged up my cat by dumping so much fuel in to it and the hesitation is caused by a lack of breathing - does this sound possible? How would I confirm this without replacing the cat? Anything else I should look for? I'm fairly confident I have combustion in all 8 cylinders now so I'm leaning towards intake/exhaust issues.

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Ford F-150 (2004-2008) :: Ticking And Hesitation / Stumble A Bit Between 40 - 55 MPH Under Load

First, a little background on my truck. 2007 with 5.4, 122000 miles, oil changes with 5-20 Motorcraft and Motorcraft filters, plugs done by dealer 40000 miles ago. The truck has developed a ticking noise, kind of like a lifter (I know these engines don't have lifters) that is most noticeable from the side of the truck near wheel. ticking speeds up with the rpm. Also around same time, between 40-55 under load there is a bit of a stumble, but I can gas thru it. I'm guessing these are related. I'm thinking spark plugs again, but shouldn't I get more than 40000 out of them? I might just take it in, since I've got oil leak somewhere around back of the oil pan, but figured maybe might get some clues first. Also, no CEL.

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Ford F-150 (2004-2008) :: 2005 - Strong Misfires Under Load

I have a 2005 F150 with 5.4 and have been having increasing random misfires. This is MUCH more pronounced when the engine is warm, and I can certainly count on it to happen when under load, either accelerating or whatever. If I am forced to remain stopped for any extended period of time, such as waiting in line at a drive through, then start to drive again, the problem seems to increase exponentially, and is most pronounced in the 1300 - 1900 RPM range. If I take the overdrive off in order to put the rev's above 2000, it eases the problem, but does not eliminate it. The issue is much LESS pronounced when first starting driving, it seems to be most prominent only after it warms up.

So far, the only codes I have ever seen is random misfires, and only once has the code gone solid in the ECM. Usually, if I back off load for a minute, it clears up on it's own and the flashing code light clears .... If I attempt to accelerate hard, even when cold, the misfires get really bad and I can always expect a hard code soon afterwards ...... needless to say, I have no real power at any time, and my fuel efficiency is beyond bad (best I can get is about 11 mpg) ....

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Ford F-150 (2004-2008) :: 2005 V8 - OD Blew Out While Carrying The Load

At work we have an '05 F150 stx 4x4 auto v8, I'm wondering what Trans it has. 4100r?

Reason I'm asking is the OD blew out while carrying a load the other day and since everyone else in the shop are Chevy/Chrysler people, I got unloaded with making the decision of what to do. New or reman trans? Try and fix it?

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Ford F-150 (2004-2008) :: 2005 F150 Misfire When Under WOT

My 2005 F150 crew had a misfire when under wot. I had been putting off the diagnosis fee for months, but I finally bit the bullet. Found out my number 3 coil was bad and the number 3 cylinder was dropping out. Dealer swapped out coil and truck runs better now. Still have to get plugs done. Truck has 88000 miles. Already had the cat replaced and didn't want to go through that again.

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Ford F-150 (2004-2008) :: 2005 F150 - Rusted Frame With 70K?

Just got bad news hours ago...frame not safe ?

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Ford F-150 (2004-2008) :: 2005 - Hesitation - Cranking But Not Starting

Quick truck stats: 2005 F150, 5.4L, 85,000 miles

The past few weeks my engine has been hesitating on some cranks before it would start. I figured it was due to the cold weather so didn't pay too much attention to it as it was also not throwing the check engine light.

Yesterday it didn't start at all after the several attempts of just cranking over and over. It still didn't seem to trip the check engine light but I pulled my scanner out anyways and it had the code p1237. I cleared it and the truck started right up. It even had no more issues the three times I started the truck after that.

Today, however, she is not starting again and not throwing any codes. Still cranking so I'm sure it's not the started or the battery. I'm going to have my husband pick up some starter fluid on his way home today to see if I can at least get a temporary start since I think it's the fuel pump, or possibly the fuel filter. It is cold again this morning so I'm wondering if the cold is somehow making this issue worse. Either way I'd like to fix it, since being stranded with a truck that doesn't start is not my idea of a way to pass the time.

What else it might be and how I might be able to diagnose it?

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Ford F-150 (2004-2008) :: Oil Leak Under Load Only?

Have a friend and looking at his truck for him. He was towing a boat and climbing a steep grade hill. As he described it, it felt like he lost all power. Did manage to get it to the top of the hill and stopped to check it out.

Noticed the under of the truck dripping oil. Checked the motor oil and none on the stick. Put 4 quarts in the motor, started it back up and oil pressure is good and motor sounds fine.

The strange thing is the motor is dry. Can not find where the oil leaked out. All the oil is located on the transmission and transfer case. I'm not too familiar with these Triton 5.4's but where could that oil possibly have come from? I'll re-look this morning.

Also, with oil in motor, and it is idling, there is no oil leak or drip anywhere. Is there a pressure regulator in this oil system and the load he was exerting cause it to release?

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Ford F-150 (2004-2008) :: Hiss When Engine Was Under Load

I have a 2004 f150 lariat crew cab 4x4 with the 5.4 3 valve. It now has 113 000 miles. Since i got it at 85 000 miles its had a hiss when the engine was under load. So like light acceleration or driving into wind. The guy i bought it from said that it had a manifold leak so that's what i figured it was. I got the manifold fixed and it still hisses. There are no check engine lights. It almost feels like my engine lags when it starts hissing. It sounds like its coming from right on the other side of the fire wall. What it could be?

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Ford F-150 (2004-2008) :: Truck Has Miss Under Load

I have a 2004 150 with 165,000 miles I sometimes pull a 5 by 8 trailer. when pulling trailer in overdrive and excelorating the engone will cough several times. I took it to a mechanic and he told me that there was nothing he could do that I needed a new engine. I can pull trailer out of overdrive with no problem. don't undrstand why I need new engine....

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Ford F-150 (2004-2008) :: No Disc And Load Error

I have a Lariat 4x4 supercrew cab with a CD 6 disc changer head unit. Error message. No Disc, and Load Error. Will not eject any of the 6 loaded CDs. Pulled/reset fuse. No luck. Banged on dash while trying to eject any of the loaded CDs.. no luck. Unit cycles when first starting the engine. Radio works fine. Unit locked up....Ford Mx tech says the solenoid that holds the CD is frozen in position and will not release.

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Ford F-150 (2004-2008) :: Rattling Sound Happens Under Load When On Gas?

Hard to describe sound, but it only happens under load. It happens at any speed, but more predominently at higher speeds. When I lift off the gas it stops. I can keep it going up hill since I'm maintaining speed rather than accelerating over the limit. The other day I heard another F150 beside me making the same noise going up a hill.

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Ford F-150 (2004-2008) :: Spark Knock Under Load?

I have a 04 5.4 w/ a whipple supercharger. truck has 104k miles. Has a misfire in cyl 4 (p0304, p0316) And spark knock.. I've changed the plugs, coil on cyl 4, fuel filter, and today the o2 sensor(pass side upper, bank 2??). I've ran tecron injector cleaner threw it, and always used Chevron 90 octane. (highest in Alaska)

The noise only happens when under load, or accelerating with more then half the throttle. doesn't happen when i slowly get up to speed. What I could do next? About to take it to the dealer to run a full diagnostic test on it.. Also, does not hesitate or bog. drives normal just with that noise

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Ford - Mountaineer :: 2006 V8 - Hesitation When Engine Is Placed Under Load

My wife has an 06 Mountaineer with a V8 and we have been having a problem with hesitation when the engine is placed under a load. The problem occurs most often when the transmission is in overdrive and the engine goes under a load such as driving up an incline at cruising speed. The engine begins to shudder much like a misfire but disappears when the trans kicks down a gear. The check engine light will flash momentarily but it never sets a hard code that I can read.

I have AutoEnginuity scan tool but there are never any codes. I've driven the vehicle with the scanner hooked up and there is never a misfire noted. The car has 96000 miles with, presumably, the original plugs. I'm aware of the potential problems with attempting to change these plugs. Where to look? I don't want to "hang parts" such as mass air flow or throttle position sensor. I've been hoping that the problem would progress to the point that a hard code would be set but none has yet.

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Ford F-150 (2004-2008) :: 2006 - Backfire Under Load During Acceleration

I have a 2006 ford f 150 with a 5.4 Triton 3v engine and every time I floor it and the engine reaches 3000 rpms the truck backfires and looses power. Sometimes it wont pass 3000 rpm it just stays there and backfire and have no power. Sometimes the check engine light flashes...... I took the coils off and looked at them and they all looked pretty clean. Also the truck idles rough and sometimes when it cruising at low rpms, and I give it a little gas the truck will randomly misfire and shake hard. also the engine sounds like a diesel engine........ What might be wrong.

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Ford F-150 (2004-2008) :: Misfire Under Load At 40 - 60 MPH While In OD Or At Higher RPMs At WOT

I have a 2006 Ford F150, king ranch, 4x4, super crew 135k miles. I bought the truck and shortly after noticed the miss under a load at 40-60 mph while in OD, or at higher RPMs at WOT, but never a CEL. Well 3 months went by and I couldn't take it anymore so with lots of research I decided to change the plugs. Ran seafoam through 2 tanks of fuel prior to this job to break up the carbon in hopes of none of the plugs breaking.

All 8 plugs came out with no issue and I replaced them with the Motocraft SP 515s (old ones were very nasty and brittle, most likely the original). I put copper anti seize on the end that goes through the channel in the head, however none got on the end near the electrode, and also on the threads. Put it all back together and it had the worse misfire an pretty much not drivable....flashing CEL and codes p0308, p0355, p0356. So I decided to buy 8 new coils as well, got all 8 of them on and now the truck is drivable but the miss is still there (no CEL).

Feels like maybe just one cylinder and I believe I got it pin pointed to cylinder 8. I put a vacuum gauge on it and unplugged the injectors 1 at a time and cylinder 8 is the only one that there is no change while unplugged. So I switched out the coil thinking maybe I got a bad one, still does it. My COP electrical plug has 12v Constant and also confirmed with an led it is getting signal. The injector is ticking or pulsing as i confirmed with a mechanic stethoscope. What am I missing????? Today when I get off I plan pulling the spark plug, checking for carbon tracking, check compression, check actual visual spark, and pull and clean the injector.

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Ford F-150 (2004-2008) :: Jerking Under Load Like Engine Is Cutting Out

I'll try to explain what the truck is doing best I can. I'm not sure if it's the engine or tranny. When you lug the truck on a hill or put a load behind it and lug it the truck jerks like the engine is cutting out or the tranny is jerking, I can't tell which. You can drive it all day long on a flat road or small hills and you can't make it do it. It does it worse going up a hill with a load behind it. You can lug the truck on a steep hill let off the accelerator and mash it back down and it will do it almost every time. I've tried overriding the overdrive and it still does it. If you keep the rpms above 2000 up a hill it won't do it. I've had it checked by a transmission shop and they couldn't make the truck do it. Also it doesn't throw any codes or put the check engine light on when this happens. 2007 F150 supercrew 5.4 auto, with 88,000 miles.

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Ford F-150 (2004-2008) :: Rough Misfire Under Moderate Load

I have an 05 F150 with the 3v 5.4 with 170k on it. Last fall we changed the timing chains, cam phasers (aftermarket), plugs, coils (OEM), VVT solenoids (OEM), Cam Position sensors (OEM) and swapped in a GT500 oil pump. Recently under moderate load (fairly heavy acceleration onto the freeway, pulling a large camper) I get a pretty rough misfire. Tonight I pulled the codes and it was Cylinder 5 misfire. In the past I have also had Bank 2 Over-Retarded code. What are the next things to verify and check? I plan to clean the throttle body and change fuel filter but I'm not sure either of those would cause the misfire code?

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Ford Fuel System :: 1988 F150 - Cuts Out Under Load?

My 88 F150 (300 six, 5 speed, dual tanks, 176,000 miles). The truck has the low pressure fuel pumps in the tanks and the high pressure pump on the frame rail setup. Truck starts fine, but cuts out severely under acceleration for the first 30 seconds of driving. After that I only notice the problem when applying a lot of throttle (does not cut out under gradual acceleration) or climbing steeper hills. If I kill it for a few minutes and then take off again the problem is back for the first 30 seconds or so. I have replaced all the tune-up type stuff (all filters, plugs & wires, dist. cap & rotor, ignition coil, o2 sensor, cleaned throttle body, replaced IAC valve, numerous sensors). Timing is dead on at 10 deg. BTDC with SPOUT unplugged. My FPR was bad so I also replaced that. Condition exists regardless of which fuel tank I am using (no problems with tank selector).

Getting no KOEO codes, but getting KOER code 41 and plugs do seem to show a lean condition possibly. I'm still averaging around 16 MPG since this became a real problem about 3 months ago.

I removed the bowl from the reservoir between the tanks and the high pressure pump on the frame. No filter in there, but it was clean with no gunk or sediment found. I removed the line from the inlet side of the high pressure pump and found that while cranking the engine I have fuel flowing freely (same amount of flow regardless of which tank I've switched to). The flow was steady, but not extremely strong. If I understand right the in-tank pumps are not designed to provide much pressure? Below is what I found at the schrader valve:

key on, engine off - high pressure pumps runs for about 1 second, brings gauge up to 48 psi

idle, FPR connected - 40 psi

idle FPR disconnected - 52 psi

revving throttle with FPR connected - 46 psi maximum

Connector, where fuel pump relay plugs in, seems to be clean and not corroded at all.

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Ford F-150 (2004-2008) :: Truck Missing Pretty Bad Going Uphill Or Under Load

I have a 2008 XL 4.2 auto trans with 60,000 miles on it. We purchased a new travel trailer with a total weight just under 5000 lbs that we pulled for about 2000 miles this summer. On the last trip we noticed the truck was missing pretty bad going up hills or under load. After we got home I started to notice the miss at times even not towing. Did a tune up with Motocraft plus and wires and seems to still have a miss at an idle and very low RPM. What would be best to check next?? Would Coil be logical?

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