305 tpi sd.

at start, cold and warm, the engine starts and idles just fine. either driving or manipulating the throttle, I get hesitation, sputtering, popping in the plenum, and surging. usually between 2-3k rpm. after that it runs fine.
there are no codes displayed. all bolts and nuts are tight. I do not see any vacuum leaks. ive adjusted or cleaned the tps, iac, and map. fuel pressure is good plugs are clean. wires tight.

am I missing something or any other ideas?

 

Test the TPS. Be sure that voltage increases smoothly with throttle opening.

 

thanks ill give it a shot. are all tps sensors basically the same for tpi? I had recently had to replace my connector and have a few tps laying around. they all don't have the same number on it, and some are adjustable and some are not.

 

If its is adjustable and you have it on a speed density set the blue wire to be .67-76 koeo.

 

I have a mulitimeter and a novice at working it. how do I check the resistance and also set the blue wire?

 

Its done with voltage feedback vdc
http://www.iroczone.com/2009/10/adju...on-sensor-tps/

 

my vss quit working a while ago and I haven't replaced it. would this affect it as well?

 

The loss off vss usually results in slight bucking during deceleration. It really sounds more like a fuel starvation like injectors.

 

you may be right. i just set the tps and its working correctly. i rest the timing to 6 btdc. checking fuel pressure, its at 39-40. its a new adjustable fuel pressure regulator and new injectors from southbay. i did adjust it and there was no difference in fuel pressure.
the fuel filter hasn't been changed in a few years. possibly its restricting fuel?

 

Had this problem with my Formula.

Modern direct injection cars are having this problem too, due to carbon deposits on the intake valves.

I'd focus on fuel components first. Does your fuel pressure bleed down with key on/engine off? If so, further diagnosis is required. A leaking fuel injector(s) will flood the cylinder(s) and cause issues at startup. Same with the pressure regulator.

 

pressure is at 12 after ignition and engine off. while running, pressure is at 39 and stays as you open up the throttle. they are new injectors and an adjustable regulator.

I just adjusted the regulator, reset the timing and adjusted the tps. im going to driving to get the ecm and engine to adjust to the new settings and go from there.