Hey everyone.
so my 2000 2.5l is periodically stuttering while accelerating. At idle it runs great/smooth, at running speeds it runs even better. Only when I am stopped at a light or wherever and I step on the gas does it bog down/stutter/hesitate almost to the point of dying. I am able to prevent it from happening by letting off the brake early and when the light changes to green, slowly give it gas. I cannot for the life of me figure out what is going on. I cant tell if it is because I put a new free flow exhaust on it but according to the company, it should not affect it. But i will mention that this problem did start very shortly after installing it. I also have a k&n intake on it too. I have changed the battery, lead wires, plugs, EGR valve and gasket, EGR solenoid, DPFE hose and sensor, IAC valve, both O2 sensors, TPS, fuel filter, fuel injectors, the fuel pump, all the valve lifters and the positive crankcase vent. I have also cleaned the air filter, MAFS and the throttle body. I have measured the fuel pressure and have gone as far as using a fog machine to check for vacuum leaks and NOTHING has panned out. I am beating my head against the wall now.. does anyone have an idea of what is going on?? Please.. for the sake of my sanity.. and the truck.. before I burn it to the ground.

Your help and ideas are much appreciated,
Thanks. Pat.

 

You could swap the computer. I had a 2004 F-150, did everything for a misfire and swapped the computer and ran fine. You couldn't flash it or anything. Replaced it ran like new as I did everything else.

Seems like you have quite a bit going on with the fuel system, air flow and back flow... the throttle compensation probably will need to be customized/adjusted.

 

Since you don't live too far from me I will go pick it up so you don't have to burn it to the ground!! LOL

You have changed out a lot of stuff! I hate to say it but "NEW" does not always mean good. There are ways to check the TPS and MAF sensors electrically. And the IAC should be a Ford part. Most aftermarket ones only work for a while if they work at all.

 

so you think it might need a tune or something?

 

I dont remember if I got the Ford IAC but I will see. If not, i will try that out. Thank you. Oh and before i burn it, I'll let you know.