Ford F150 Acceleration problems!
 

Ok, I have a 1998 Ford F150 4.6 liter. My problem is the truck will barely move from a full stop cold or warm make no difference. If you lightly push the accelerator it will slowly begin to move then after about 20ft it will finally kick in and go, but will also choke and shutter if you try to accelerate normally. I have practically replaced the entire ignition system! Including the plugs, the plug wires, the ignition coils, and the Crank position sensor. I have also replaced the fuel filter, and a mechanic checked my fuel pressure and fuel injectors and said they were fine! No one can figure this out and I'm over $300 in and have gotten no results! Can anyone help????:(

Could you possibly have a trans converter problem?
There is a one way clutch for the stator in the torque converter and when this clutch doesn't lock up as required, you get no torque multiplication which you need to get the vehicle moving.
There is no way to confirm this without removing the trans and actually checking the converter itself.

I did just install a used transmission. But How can I tell if the converter doesn't work properly? It simply bolts to the flywheel. How do I determine there is a problem with it? even if I take it out? It's just a big canister.

I had the same problem before I changed the transmission but it wasn't as bad as it is now. Man this is making me crazy I've spent the past several weekends working on my truck and spending tons of cash and I'm getting no where!
Thanks

I need to know a few things, if you would.
Why did you change the trans? Did you use your old torque converter or did you use one that came with the trans , if it did?

My original Trans would not shift at all. I drove it around for almost a year by putting it in second gear, so I could at least drive around town. I just couldn't afford to repair or replace @$1,200-$1,500! I finally fond a used trans for $250 on Craig's lists. The used trans came out of a 97 f150 with the same size motor. The only problem I've encountered is it won't shift into overdrive. The overdrive switch on the column does not work. But since my truck barely moves now I wasn't worried about that just yet. I assume it has something to do with the electronic portion of the trans. I was told that would not cause my problem though. I did use the torque converter from the new or used trans.

If you have the older torque converter, you put your finger in the opening and can feel the stator center. Try to rotate it , it should move in one direction ,but not the other.
Thats how you check it . A one way clutch will allow it to turn in one direction only. If it can rotate in both directions , its defective. I'm not quite clear on just what you are trying to describe as choke and shudder. If you mean the vehicle kinda bogs down, then that would not indicate a converter problem.
A clogged exhaust converter can cause the vehicle to lack power and just doesn't want to go.
We need to be careful when using parts from different years of vehicles because they make changes from year to year and this can sometimes drive guys nuts.
Did you remove an E4OD trans and replace it with an E4OD trans?

I don't know what you mean by E4OD? Is that marked on the trans?

I'll try to describe my problem more clearly. When you first put the vehicle in gear, it wants to stall out and some times it does not want to move at all. The engine does not rev up, no matter how much or how hard or soft I push the gas peddle it just won't move and wants to stall out. Then slowly it will begin to move and after about 20ft it seems to kick in and go, but still if you try to give it more gas it will kind of bog down before it accelerate. It will drive OK once you get moving as long as you accelerate smoothly. If you come to a crawl you can still accelerate and get moving again without to much problem. But if you come to a complete stop it wants to stall, then is hard to get moving again. This is very frustrating! I appreciate all your input. Thanks for your advice.

Hang on , we are gonna move out now!!!
First; E is for electronic, 4 is for 4 speeds.OD is for overdrive that said lets get to the real problem.
The symptoms you describe sound like your converter clutch is staying engaged and not releasing. There is a converter clutch solenoid in the trans that applies or releases the converter clutch. When the clutch is applied (lockup) you have a direct connection from the flywheel to the trans, no fluid coupling with some slip. Thats why your truck wants to stall when you put it into gear. Now what you need to do is find why the solenoid is not allowing the clutch to release. Normally the ECM gets a signal from the vehicle speed sensor on the trans and that with signals from tps ,map sensors will cause the CC (converter clutch) to engage. I would consider changing the speed sensor with the one from your old trans first. if no change, the solenoid body in the trans is suspect. You should have received a code for this . Lets see if this corrects the problem.

also check catalytic converter

Thanks I'll try that!