Driving home today my truck started bucking like a pissed off mule at part throttle at lower rpm's (<2000). Past week or so the truck would die at start up until she warmed up a bit. Have to keep feeding a little bit of throttle for a few minutes. As bad as it is running, I can't believe that the check engine light never came on. If I punch it and get it to down shift, problem goes away. I had a shift kit installed a couple of months ago (fairly tame settings) and has been running fine until now. Did a bit of searching and don't think it is TC shudder as it does not matter what gear I'm in, not just close to a shift point. Would the IAC cause this and not throw a code? Was messing around under the hood a couple of weeks ago installing the Sylvania HID kit. Anything I could have knocked loose? Didn't see anything that looked wrong.

Any ideas?

 

is it a 4.6L or 5.4L ? in my crown vic (4.6) i knocked loose a copper colored tube by the EGR area and had the exact problem you're describing, it would come and go.. i figured out where it was because there was a hissing sound when it ran rough. just tightened that tube up like it was supposed to be and it never bothered me again.

 

Misfiring?

Get the codes read anyway, some codes dont always set off the CEL, but they are stored.

 

I have what sounds to be an issue similar to yours and it's driving me nuts! I'm not a mechanic so that makes it more frustrating. I have a '95 F-150 351 4x4 SuperCab and in the last 3 months this shuddering at low rpms between 30-40 mph the truck on the throttle rattles like it's going to fall apart.

I changed the plugs, wires, cap, and rotor and it seemed okay for about 10 minutes and is now worse. The motor mounts seem fine and everything underneath looks ok. I've replaced the u-joints as well?

Any hints or suggestions? I may have to bring it in if I can't solve the problem.

Thank you
Daryl

 

Sorry, forgot to turn on my sig. I'm going to look up how to disconnect the TC lockup solenoid and take it for a test drive. If it is TC shudder due to the torque converter trying to engage, then it should drive smooth with it disconnected in theory at least. May not be easy to disconnect through, if I remember correctly, the TC solenoid connector is inside the tranny pan. Anybody tried this?

I'll run up to Autozone for a quick code read and see if they have anything first though. This is quick and better yet, free. It does have 130K so maybe I'm losing a coil. Thought this would have lit up the CEL, but maybe not. Changed the plugs at 100K so those should be ok.

I want to exhaust all of my testing options before I start replacing parts on a trial and error process to find the problem.

 

Finally dug into my Ford Factory Service CD. Man does it have a ton of info on diagnosing problems. Even has definitions so you can correctly understand the differece between a shake, shimmy, and shudder according to the automotive world!

For instance, did you know that a shake is a low-frequency vibration (5-20hz), usually with visible component movement. I think it is hilarious that they have technical definitions.

The CD was perfect for diagnosing the problem as it has all kinds of tests to run to help diagnose the problem, many are simple driving tests. Based on what I have read and taking the truck out for a test run, it is definately TC shudder. Know I just have to figure out if it is the solenoid (I hope) or the TC itself (sounds expesive and time consuming). I'll post again if/when I figure it out.

If anybody else has a shudder that they think is TC, get your hands on the Factory Service CD. It has been a life saver working on this truck!

 

Cross,

Where do you get the CDs from?

Anthony

 

You can get them from Ford, but I heard they are outrageously expensive (hundreds of dollars). I found mine on ebay. Try this. Cheap and easy. I paid around $20 bucks for mine. I'm sure these are bootleg so buy at your own risk. They are a huge help. I couldn't imagine working on one without it.

 

Cross,
SOunds like I am having the same problem that you have. I just got the CD that you mentioned, (paid $10.90 for it, not too bad), it should be here in a few days, but until them could you expound on your findings. What is TC? Sorry, I'm new to working in the engine bay of anything newer than 1979. The truck shudders at low RPM and now it is lagging a bit when I open it up. It wants to go but then slows and picks up again. Guess I'll be trouble shooting this Labor Day weekend to fix it.

 

TC is the torque converter, hooks your flywheel to the transmisson in short answer.

 

back to the original question...
I had the same problem with the engine. went to parts store, no code. ran it another few days and the problem was getting worse. Went back to the parts store and now got a code.. #6 misfire. A new COP and it's running fine.

 

Have the same problem on my 2005 supercrew4x4. i think it just goes along with the poorly designed motor. I have 8000 miles on mine and the miss is getting worse. actually sounds like the motor stalls then starts again. Ford says they are working on the problem but till then drive it. in fact head mechanic said to (drive it like you stole it) along with the miss it gets 11 mpg city and around 13 hiway. what a joke but paid too much to trade it just yet. loved my 96 f250 crew cab traded it in with 248,000 better truck than this 05. maybe i drive em too easy but its a truck not a hotrod.