Yesterday I experienced what I'm going to call "bucking" when my 2001 4x4 F150 Lariat is between 3 and 5th gear. It just started yesterday afternoon after about a 20 mile drive. Upon slow to moderate acceleration, when the truck gets to about 40mph I can feel a noticable "bucking" until it gets into 5th gear. At highway speeds the truck runs smoothly. There are no engine lights and the "bucking" is the only noticable issue. Between 40-50mph the truck feels like it's hitting little holes in the road.

This truck has always had what I consider a "rough shift" getting into 5th gear. You can actually feel the truck lurch when it shifts into 5th gear. I've already been through and fixed the wet coil pack and spark plug problem back at about 45,000 miles. I now have 67,000 miles on the truck. As alot of Ford owners have experienced, I too had to go through the excessive carbon buildup problem and the 8/9 cylinder deal with the wet coil packs and fouled plugs. All told it cost me about $1000.00 to get it fixed. Hadn't had a problem since. Now this.

Also, I installed an Airaid intake system about 700 miles back but there is no indication of a problem with this.

Why do I have a suspicion that my transmission is about to go ****-up?

Any advice?

 

I would check your spark plugs and other ignition system compnents. It sounds like you have a (serious) miss going on.

 

I took my truck to Firestone a couple hours ago. They just called and told me everything checks out fine and they suspect my Airaid intake may be causing the problem. I've put 700 miles on the truck since I installed the intake. No engine lights came on after installation and the truck had been running fine. Why would an aftermarket air intake cause problems with the truck accelerating? The hoses are correctly installed and not pinched off, the MAF is installed correctly, the filter isn't wet and as far as I can tell all the couplings are tight. As I said, the problem just became noticable after 700 miles driving with the new intake. Boy, I'd hate to have to reconstruct the stock Ford air intake !!

Also just realized I filled up with gas yesterday. I'm wondering if I didn't get some bad gas. Firesteone says their computer diagnostics are all NORMAL. I have to drive 250 miles to Miami on Sunday...not looking forward to that with the way the truck is running!

 

I could be a bad tank of gas.
Also, it is possible that maybe you over oiled the air filter, but I suspect that would set off some codes because your sensors would be getting fouled up.

It wouldnt hurt to put the stock intake back on and see if that is your problem.

 

Before I get going on this...I didn't oil the filter at all. Nothing inthe installation instructions mentioned oiling th efilter.

The mechanic told me to put the stock intake back on as well. I really don't want to have to do that. I called Airaid. They said there was no way the intake could be screwing up the engine unless there was a loose hose or something. Airaid told me to try to reset the computer and see what happens. Meanwhile, Firestone says without a "check engine light", the computer isn't registering a code therefore they don't know anything.

So, I'm at a loss and I work 250 miles from where I live. Seems odd that it would start happening less than 1000 miles after installing the new intake. Then again, I do have 67,000 miles on the original 02 sensors. Plugs and coils are only about 22,000 miles old.

Firestone also said it COULD BE a clogged fuel injector, fouled plugs or bad coil packs...but since they don't have a code, put the stock intake back on and wait for a check engine light. otherwise I'm wasting money on the flip of a coin that any of those things COULD BE the problem. Meanwhile, I'm looking forward to being broke down alongside Alligator Alley in the Florida Everglades trying to get back and forth to work.