Having similar problem but mine is when I nail the gas, car almost bogs out and dies, THEN picks up and accelerates like a champ. Let me know if you find anyhting before I do!

 

Im no expert, but your problem sounds like the throttle position sensor. The guy I talked to (fairly knowledgable old timer) said that when the TPS is bad it will usually have a dead spot.

Mine isnt a dead spot, its irrattic RPM's while idling and while driving. When Im cruising along it seems to do it worse than if I lay into the throttle, it almost feels like the car hits a bump, you can see the RPM's jump on the tach.

I really need some experianced advice here guys, I cant afford to just start throwing parts at it. My guess is its either MAP, injector or TPS related, if anyone could help me on how to check these parts out to see if they are the problem it would be greatly appreciated.

 

I am also having the problems above that you stated with the RPMS jumping and acting all crazy. I thought it may be a vacuum leak so have started troubleshooting the miles of BS vacuum line under there. I also noticed my IAC harness is broken. with the car in gear and a friend in the brakes I took and unhooked it and it made no difference. But one thing I'd check is if you have a vacuum controlled EGR, check the vacuum on the port in your throttle body and then make sure all the lines are alright, and make sure the vacuum lines are not reversed at the EGR solenoid. This will play hell with your engine RPMs and create false misfiring.

 

The lines shouldnt be crossed, I didnt mess with anything and it ran great before. Is yours only doing it in gear? Mine does it in park too, but its not as noticable (unless your looking at the tach)

 

Bingo... we've got the same problem. Well I've heard but haven't done it yet, but you can unhook the vacuum line to the MAP and see what it does, should throw an error code.

 

Well I started the car up, let it warm up and start pulling hoses and wires off of sensors. All of them seem to be working, dont know if its working properly, but I could tell the differance when I disconnected them.

I took a can of carb cleaner with a straw and stuck the straw down into the injectors and sprayed from several differant angles. I think I knocked some crud loose cause the car smoked like a frieght train for a minute and now it seems my surging with driving problem has mostly went away. It still has an irractic start up idle and a high overall idle, but at least they surging seems to have gone away.

I think I'll rig up some sort of attachment for my vacuum cleaner where it has a small hose it sucks through and I'll take the EGR off and break up some of the crud around intake and suck it outta there.

 

Well turns out I was wrong problem didnt go away, but Ive got a better understanding of it now. It only does it at part throttle, when Im barely pushing on the gas, when Im cruising around 2000 RPMs, seems like over about 2200 RPMs and it doesnt do it. I can cruising at 2000 RPM (approx 60MPH) and while it stumbling/surgeing I can lay into the gas and it clears up.

This problem is not major its actually kind of subtle, with the roads here its hard to notice it.

 

I was told carbon build-ups in the tbi unit does funny stuff to cars....

 

did you ever get to the bottom of your problem? I just registered on the site and reading your problems is almost the same as mine. i have a 91 RS camaro, V8 with the throttle body. i first starting having the same problems, but they seemed to dissapate after the car warmed up, but the ruff idle at a stop and the bogging down or labored RPM were still apparent. I went through tracing vaccume lines initially, then changed out the EGI valve, which actually helped it a little. The last thing I did was to mess with the fuel system. I pulled out the injectors and cleaned them out really well, but didn't replace the little filters. Initially I didn't replace the gaskets, just to see if the problem got any better, or worse. It probably was leaking a little gas which made it idle a little higher/better, but it made a lot of smoke out of the tailpipes when I hit the gas. I went back through it tonight and replaced the gaskets and put the throttle body back together. It works better now, but still not perfect.
Sorry for the long email, but if you have any more suggestions, I would appreciate it.
Thanks.

 

Same problem but im on TPI Ive done a full tune up. 40PSI fuel pressure, no vaccume leeks around the intake or engine bay. New ICA Timming ajustemnts dont help, ajusting the ICA, min air, and TPS it still surges in park, and drive

Runs fin when it cold start mode tho then after warming up it throbs.