ok so i have been driving around my fc since november, had no problems...it sat for a while before that, then on friday it started giving me a problem..at first it was while i was driving.. id be accelerating, then itd get to somewhere near 2k and it would hesitate and jerk, just lose its power, so id get off the gas and then get back on and it would hesitate for a little then progress a little..it doesnt really seem to do that once i get above 3500 rpms though..and its also doing at while idling now..i had changed the fuel pressure regulator, changed the fuel filter, changed the spark plugs, changed the air filter, i really dont know what else to try..i have this feeling its my primary injectors, because to my knowledge, they would control under 3500 rpms, which is where the problem has been occuring, or maybe could it be the air flow meter? anyone able to provide me with any help or suggestions? id greatly appreciate it! thanks.

 

hm well now it seems to be doing it even above 3500 rpms...this sucks

 

Dirty Injectors maybe? It maybe a waste of time but try running down your tank to about 1/8th full and pour in some cans of "Seafoam" it is good at cleaning and eating out grime from your motor.

 

yeah basically, i just unplugged the top 2 injectors...(secondaries?) have em both unplugged and the car runs the exact same as it was..so my best guess would be dead injectors..does that sound right?

 

is it possible for it to be running poorly like this due to a bad air flow meter or throttle position sensor? need help asap, thanks!

 

Under 3800 rpm, only the primary injectors fire.
Above 3800 rpm, both sets of injectors are used.

What rpm did you get the engine up to after you unplugged the secondaries? If it wasn't at or over 3800, then it doesn't prove anything.

Go ahead and test your TPS: http://howto.globalvicinity.com/gv_w...i=58&co=1&vi=1

You can used the 2-light method to see if it's adjusted to within spec, or you can backprobe the "A" terminal and check that it shows 1.0V when the engine is fully warm and the key is to the "ON" position.

The problem is obviously mixture related, but with as extreme as it sounds, I'd be leaning towards the fuel delivery side. A fuel pressure test wouldn't hurt either.

 

well yeah i can rev the car up to redline, and sometimes it hesitates, even with th esecondaries unplugged..its just somewhat difficult to get the car above 3000-3500 under load, so i really dont know..im really unfamiliar with this, hence i posted up on here..i appreciate the link and information you have provided.