hey problem in 91 RS

okay i have a slight problem in my 91 camaro RS it differs slightly each time in the speed but between 30-40 mph i get a julting in the engine sometimes. the feeling is kinda hard to explain but its like the engine is jerky pretty bad and almost feels like it wants to die or choke out but only happens at this speed when more gas is givin or my foot is taken out of the gas its fine... ive read up on here and found a similar problem but at a lower speed like on when crossing speed bumbs, your suggestions where that it might be a build up in the idle air control. i was wondering if i am probably having the same problem with mine.
any help or suggestions would be appretiated and by the way i have the rs w/ the 305 tbi i do at least know that much....
email me or im me or u can just post on here if thats the easiest way

i dont think the IAC is your problem, but you can clean it and find out. does it make a difference if the car is in drive or overdrive? if the converter is locked up in overdrive at 30-40mph, it will pull the RPM's down and try to kill the engine

Also check your air filter, a clogged air filter will do that too. Throttle possition sensor. Check anything that controlls how much fuel is injected into the intake or anything that could restrict air flow into the throttle body.

that's what mine did right before the ignition coil went.

there is a known problem with third gens regarding this. when drivnig in overdrive, at 45-60mph, and the cooling fans come on, there can be a condition that the vibration of those fans sound like the vibration of the engine detonating to the knock sensor, and it retards timing, this changes engine speed, and poweroutput, making the converter unlock, then the conditions return to normal, sensors tell the converter to lock up, then the knock sensor retards the timing and so on and so forth. if your rpms are dropping by a few hundred, then going back up, then dropping a few hundred, then going back up, that is more likely than not the problem. however, the shitty news, there is no fix for it. :( the only thing i have heard to try is buy a new fan motor, and the vibrations may be different enough to not cause the problem. i know mine started diong it, after i put a new fan in, after the old one burned up. you could also try insulating the fan somehow, but im not sure how you would do that. its already monuted on rubber stoppers i think. also, when the car is doing this, watch to see how many rpms drop off. then downshift into third. if the downshift is more rpms than the drop you saw before, than it is the converter, if the rpms are the same then its actually an internal trans problem with the fourth gear servo or something, i forget what its called. cuz its actually dropping in and out of fourth gear. could also be a bad TCC switch. the only reason i know all this, is im having the same problem with my RS, and have yet to track down the problem. ill let ya know if i figure it out.

well i tried just driving in drive instead of overdrive today and i have yet to have that problem w/ it so that might be it

yup, sounds like its either the TCC switch, the fourth gear servo (or whatever) or that condition. did you compair the rpm drop from fourth to third, to the rpm drop when its acting up??? which one is more rpms??

no i havent looked at the rpms yet and i do have an automatic so ill have to pay close attention when it shifts gears ill let ya know

The same thing kinda happened to me. Execpt at low speeds when i gave it just a little gas and let off the gas pedal real quick it stumbled and it sounded like it was choking and wanted to die. Try removing the EGR valve vacuum line and just cap it off. If that stops the problem then all you have to do it keep it caped tell you have to get it smoged. Then you have to get it replaed.