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

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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Pontiac - Montana :: 2004 - Hesitation Or Stumble As If Engine Cuts Out For A Second

I have a 2004 Pontiac Montana with 90K. If the overnight temperature has been below 40ish, there is a noticeable hesitation or stumble (almost as if the engine cuts out for a second-but never actually stalls out) on the 2 to 1 downshift when braking to a stop while the vehicle is in open loop. As the engine warms up the stumble becomes less noticeable until the temp gauge reaches the 1/4 mark at which point the stumble is gone. It won't return until the following morning - the next cold start. Our mechanic has cleaned the Throttle Body and the MAF- no change. Their transmission guy said he did not think it was a tranny issue. It has no other symptoms and seems to shift normally at all other times. What to do next??

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Ford F-150 (2004-2008) :: Stumble While Going Down The Road Between 40 - 60 MPH

My boss' truck has a bit of a stumble. While going down the road between 40-60 MPH it will kind of stumble. While it's an intermittent problem, it seems to happen when climbing a slight grade. I plugged a diagnostic tool into it and got no codes of any kind. He had it at a trans shop, thinking there might be some trans slippage, but the shop said the trans was fine. The vehicle in question is a 2006 F-150 Lariot 2WD with a 5.4, auto trans...

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Ford F-150 - 1997-2003 :: 1999 - Engine Stumble At Load

1999 4.6 (106K miles) will stumble / miss when at 35-50 mph under a mid throttle load (just before reaching the downshift point). Has been doing this since I bought the truck at 70K miles.

Computer has no codes, engine runs fine under all other circumstances, and gets a decent ~20 MPG on the highway.

Done the standard tune up items (plugs / motocraft) and cleaned MAF, replaced TPS, tranny flush/ filter. Replaced the left O2 sensor 2 months ago, but it dumped a code and was really noticeable when it went out.

I am about ready to dive off and replace the MAF, but at $100 a shot would like other alternatives to try first. I am really convinced the engine is leaning out and misfiring under this load.

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Ford - Focus :: 2003 - Stumble And Hesitation At Steady Speed

I have a really weird issue with my 2003 Ford Focus. Manual transmission, just over 50,000 miles. I've been noticing a stumble or hesitation (like the engine is cutting out) at steady speed, but ONLY when it is snowy out, more if it's windy as well. I don't recall that this happens if it's rainy or foggy. All maintenance is performed as specified, to include air filter changes.

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Ford Excursion :: 2000 - Hesitation / Surge And Stumble Over 1500 RPM

I recently picked up a 2000 Excursion with the 5.4 V8. Engine has 150,000. I got it cheap because it has a surging problem over 1500 RPM. This problem is intermittent.

I have 1 DTC. P1000 which is OBDII checks not complete. I cannot clear this even using the factory procedures. FYI..I have a snap on solus scanner. I think this is a voltage problem, If you try to start the engine with the scanner plugged in, the scanner shuts off, so I'm thinking the PCM loses battery power supply when the starter engages, resetting the PCM.

This problem is NOT a miss.... something isn't opening or shutting off above 1500 RPM. This truck doesn't have an EGR system, it has the EVAP system. This may be the problem, thats why I'm here. OK. heres a list of what I've replaced since I started working on it.

Engine oil and filter
air filter
fuel filter
8 COP's
8 plugs gapped properly
cam position sensor
IAC sensor
MAF sensor
Removed throttle body and cleaned.
Vacuum checks. 22" at purge valve,fuel dia, and vacuum canister
Checking with the scanner at 1500 RPM with problem
SFtrim1% bounces between5-15
SFtrim2% bounces between2-0
LFtrim1% bounces between11-13
LFtrim2% bounces between 5-6
O2S11(mv) bounces between 200-781
O2S21(mv) bounces between 200-800

Ssystem is in closed loop holding throttle at 1500 RPM... Note engine surges when at the RPM or above. I'm thinking the engine is lean, not sure how to read the trim numbers...

Idle is fine ... Problem is intermittent ... Also noticed that engine will only advance spark to 30 degrees @2000 RPM during this problem. I have seen it advance to 38-40 degrees when I do not have this problem, so I kind of understand the power loss,knock etc due to the timing, my question is whats causing it to do this?

EVAP question.... The purge valve should open according to PCM command a certain value, correct? I can monitor the duty cycle % but cannot activate and check proper duty cycle through scanner . When I try to I get an error message of module error -unspecified.

Disconnected hoses at purge valve,Full manifold vacumn on one, nothing on other, no flow through purge valve, but scanner shows 30% duty cycle. I would think the should be a little flow at 30% Maybe my problem? Troubleshoot procedure for the EVAP would be good.

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Ford F-150 (2004-2008) :: 2006 - Stumble When Accelerating Around 45 MPH - Misfire On Cylinder 5

i just picked up an 06 f150 with 5.4l 4x4 xlt package. Love the truck as it is my 1st Ford HOWEVER..... the truck is running super rough at idle and keep getting code for cylinder 5 misfire and bank 2 lean (which i am assuming is from cyl 5). here is what i have done so far...

New Coil packs
New spark plugs
New fuel module
New fuel injector on cyl 5

Still has a "stumble" when accelerating around 45 mph and shows code for cyl 5 misfire then will then throw code for bank 2 lean.

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Ford Fuel System :: Mild Stumble / Hesitation When Dropped In Drive

460, stock RV motor with LT headers, Alum Stealth intake. Carb is brand new, Holley 600 cfm, out of the box.

Elec choke, vac 2nds. Timing is set to 12 BTDC.

Truck idles beautifully. Drop it in drive, it will ever so slightly stumble/hesitate then go liked a raped ape. Has great acceleration (for a 8k dually crewcab). In my mind, I'm thinking a slightly larger than stock accel pump to give a bigger shot.

However, it does have a 1" carb spacer. That and the hi rise stealth, is it leaning out for a sec and causing the stumble? Would pulling that 1" spacer work? I was thinking the higher the carb the better to get less heat dissipation from the engine's heat. Replacing the heater core now. So I have some time to sort it out. I'd like to road test a tank of gas through it, but gotta fix the heater 1st.

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Ford F-150 (2009-2014) :: Slight Stumble / Hesitation When Start The Truck Cold

A couple questions I have about my truck. I'm still new to the F150.

First, my truck has an Ecoboost and I have a slight stumble/hesitation when you start the truck cold. It clears up within 10 seconds and doesn't seem to affect drivability whatsoever.

Second, it seems that only my driver side mirror has the "dimming feature" to it. Is this normal?

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Ford F-150 - 1997-2003 :: Slight Miss / Rough Idle - Hesitation Or Stumble On Acceleration

2003 F150 5.4 72852 miles

I have a Rough Idle & sometimes a hesitation or stumble on acceleration. I cleaned the MAF & IAC motor & Air & Fuel Filters are new. I got a 20890 scanner & ran test 6 53 as suggested in many posts by BlueGrass. Here are My results & what They Convert to.

1 00F5 .3675
2 0051 .1215
3 0000
4 0000
5 00A3 .2445
6 0000
7 0000
8 0000

I'm guessing the cop's are ok & probably need plugs? I was hoping to just swap a coil. Too cold to do plugs & truck won't fit in my garage.

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Accent MC (2006-11) :: Hesitation Or Stumble On Light Acceleration That Come And Go

My 2011 stick shift no air Accent has a hesitation or stumble on light acceleration that comes and goes. It may not occur for weeks then re-occurs. It is hard to reproduce intentionally. It never occurs in cruise. The CEL is not on. Most often occurs at 1400 to 1500 rpm with slight acceleration or a slight increase in load as coming to a slight hill. I tried injector cleaner a few times and changed air filter. It seemed more reloaded to induction airflow so I changed the MAP sensor. I understand the 2011 Accent does not have a MAF sensor. It is still occurring. It is fine in steady cruise as well as in hard acceleration. I am wondering if it is a TPS sensor problem. It has 60,000 miles and otherwise runs fine.

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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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Silverado :: 2000 Tahoe V8 - Hesitation Or Stumble Under Acceleration Or At Steady Speed

I have a 2000 Tahoe with the 5.3L V-8, 351,000 (yes that is correct) miles. Runs great except it has recently developed a stutter, hesitation, skip, I don't really know how to describe it, under acceleration or at steady speed. This is an intermittent problem and it is driving me batty. The only codes are a P0420, maybe after 350k miles it needs replaced? Would that possibly cause this issue, or am I looking at something more sinister?

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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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