I have a rebuilt 350TPI in my 92Z. Doesn't matter if I'm cruising down the highway or along back roads, doesn’t even matter what RPM I’m at. If I give it a little more throttle the RPM’s drop for about ½ second before climbing, it’s enough to cause the car to “buck”. I thought it might be the TPS but I replaced that it it’s still doing it.

Rebuilt 350TPI
Plenum, runners, intake base all extrude honed
Cam “Specs at home but I know that I am maxing out the valve springs”
Eldlebrock shortie headers, dual cats 3 inch cat back!
Hyperjunk chip!

That’s all I can really think of at the moment, any suggestions would be GREATLY appreciated.


-Marc-

 

Hey Marc, lets try 3rd Gen Tech first as that would be more appropriate for these questions. Thanks bud.

 

There is a place in the computer called the "pump shot" or "acelleration enrichment" that will give the car more gas when you step on the throttle. Since the car has significant mods on it, like the new cam, the computer isnt giving it enough gas and you're running lean, hench the stumble. Your best solution is to find a friend who burns custom chips and have him/her do one for your car. He/She can increase the pump shot to help you out.

 

You may have to burn a custom chip or simply have your system recalibrated. With the mods you listed that may be the problem.

 

You could go to www.fasterproms.com and they will burn you a custom chip and have you take readings and reburn twice to get it right on. However, I would first investigate the springs issue. Maybe you have a broken spring, valve float, or whatever?

 

Thanks for the info gius, I'll check into having a chip burned.


-Marc-

 

it doesnt sound anything like valve float, if the spring was broken, your car would run like crap, not just stumble - if your spring is binding, it wouldnt be just at higher RPM, it'd be at any RPM and **** would be breaking, resulting in the car running like crap. get an adjustable fuel pressure regulator n bump up the pressure n see if it helps, with cams not much larger than stock duration, thats crane cams solution to not needing a new chip.