c2369zulu

Hello Everyone!

This is my first post, so I will try to make it a good one. I know this has been been discussed before many times and have read most all of these discussions, but for the life of me, I cant figure it out and neither can Ford. This issue is the stutter/hesitation at 45-55mph under light load and sometimes on flat road. I have no MIL light on, no wrench light, no codes. Normally happens when you ease up to 45mph, slowly let out so rpms drop a little, then roll back into accelerator, then rpms drop slightly and then dun dun dun dun dun. If you let off the pedal it comes out of it. It also comes out of it when the throttle is depressed harder. RPMS jump up fast when throttle is depressed a little harder.

I have taken my vehicle to the Ford dealership approximately 4 times for different odds and ends in the last month or so, but always with one issue in particular and the title of this thread describes it. The technician has used his computer software and 3 road trips with me driving and still can't figure the issue out. His software shows no misfires and he does not believe it is the torque converter or tranny. The computer was not hooked up while driving BTW, just at shop, go figure. He says he really thinks the sound is like a very small exhaust manifold leak, but I dont think so. I know that the fixes for some in the past have been new torque converter and or new coils for those misfiring. I replaced all of the coils and plugs, all of the injectors, and the TPS.

I ended up picking up a scantool to see if I could figure some of this out myself since I drive it everyday and spend more time with the truck. I used the ACTRON 9580 tool. This is what I found that I thought may be odd, although maybe it is supposed to do this:

I notice that when the issue occurs while reading the live data on the scantool, the ABS TPS (Absolute Throttle Position Sensor), The throttle command actuator and the REL TPS (relative throttle position sensor)all jump to near wide open throttle. In other words if they were all around 37-40% while approaching 45mph, they all jump to around 70-90% as if the throttle is wide open. I just installed a new TPS on the TB, so I assume it is reading where the actuator is positioned. 45mph is near the O/D point right, so I thought maybe the PCM was telling the throttle to open without my control for the O/D, but if I press the accelerator a bit more to get the truck out of the stuttering state, the passing gear kicks and the throttle position is only around 50ish %. So, is the actuator actually going to WOT at this point, causing too much air to be sucked in, making the mixture too lean to be able to fire, hence causing a stutter? What do you guys think?

Thanks everyone.........Rory

Mikechek

Wow, you couldn't describe this problem any better. I have the same problem. I took my to the dealer and they did the same thing. I test drove with the mechanic and his computer hook up to it. And he could find nothing wrong. But same thing he said I had a manifold leak. So they replaced the gasket. It got a Lil better but it still doing the same thing. I hope some one could help us out. This is driving me crazy.

c2369zulu

Thanks for responding. Yeah, this is driving me nuts also since it is at the point where I have been just throwing parts and $$ at it with no luck. The part that bugs me most is not knowing if further damage is being caused elsewhere because of this. It also does not make sense, atleast to me, how an exhaust manifold leak would make the both the rpms drop like they do and the accelerator pedal to have a dead spot where you are pushing it, but nothing seems to be happening until it jumps out of it or you let of. You can accelerate through the issue if you dont ease up on the throttle. Its mainly when feathering the pedal on low grades and curves, etc.

Mikechek

yes mine is the same. It's when you accelerate it doesn't do nothing. and if you step on it downshift and then it catches. the other day i was loaded and that 45-55 speed it felt like my truck had no power. I am taking back to the dealer and going to ask to speak to QC leader. and im not going to leave until i get a answer. this **** sucks. Also you sould try posting this on 2004 to present side of the the forum. More people get a better look at your post. Might get the ansewr there. I posted this same problem but not as deep as your.

Mikechek

To give you an update i took my truck to the dealership today because one of my front caliper froze up. So it was going to take 3-4 hrs, so they were forced to give me a rental. But, at the same time i told them that i still had that same problem 45-55. When the mechanic drove it he told services righter that he didnt feel anything. So they called me to tell me this bull@#$!. Imagine i live about 1hr from the dealership. i left my job on the spot so i can test drive it with the mechanic. On the test drive with him he told me it was normal. at this point i ask to speak to the manger. On this test run he came with use. After driving it around for a little while he told the mechanic there is no way possible this is normal. So after a while of me bitching they insisted that its a exhaust leak some where. They told me that they are having a ford QC coming to see it on monday. Lets see Monday what bull@%$!. they come up with. I told them i was going to call headquaters and let them know what was going on. See im lucky right, i just bought this truck around 40 days ago from the ford dealship and it came with 60 days unlimited warrenty. So am going to push every problem to the end.

Hamilton77

It seems the engine stutter problem isnt just the 5.4 engines, it's also the 4.2 V6 has that problem too. I've checked everything (vacuum lines, sensors, and yes exhaust and all are ok.) it shows no codes and usually stutters around 45 to 55 mph. My truck is 2006 F150 STX 4.2 97,000 miles and it started doing this 4 months ago. Anybody finds a fix please post!

Mellowyellow

My 4.6 did this in my old mustang,

c2369zulu

Well I certainly wish you luck. Keep us updated as to what is found. As mentioned in my original post, the only thing I have found strange is that when my Actron Scantool is hooked up, I notice several Throttle Positions shoot up to wide open when the isse occurs. Not sure if this means the actuator on the throttle body is bad (already changed the TPS) or if it is the PCM telling it to do this for some reason. Not sure if it is related, but I am also starting to hear more "pinging" and "tinging" sounds (like thermal sound when engine is cooling off), but while hot, running and driving along. Never done this before as far as I recall. A/C not on so I dont think it is condensation dripping on anything. I am wondering if it is normal or if it is something in the engine or transmission. I looked at my foam liner on the air filter tray as mentioned in the sticky about the moaning and it was almost completely worn off. I rolled up a blue shop paper towel to wedge in in its place to see if there was a difference in performance if sealed better. No difference. I think this is just a piece of foam that assists in keeping dust from coming in and really has no affect on the amount of air coming in, however the original poster of that thread said it helped his issue. Still banging my head.............Rory

riptide1

Hi everyone! New to forum, my 2007 with the 5.4 is doing the same thing at around 40-45 mph city driving under light throttle. It doesn't do it under green light gas, but as you let off and keep pace with traffic then go to give it gas it stutters. Changed the fuel filter thinking this could have been the problem, but it's still doing it! Any insight would be greatly appreciated! Thanks

Jsanchez1wright

Hello everyone, hate to jump in the thread but I own a 2004 Supercrew with 100K and it does the exact same thing. I just did a spark plug service on it. Which helped other issues. But this one is a bit weird. Hopefully someone shares successful findings soon.