i have a 88 camaro with a 305 tpi... it has no smog no egr (it was like that when i bought it) the problem im having is the engine misfires at idle and stumbles when crusing when i get heavy on the throttle i really cant hear any misfires or feel the engine stumbling at all i have replaced cap rotor plugs wires and coil fuel pressure is 42psi KOEO 35psi KOER 42psi KOER with vac line pulld off the regulator i really cant find the timing this car likes maybe if some one can give me a course::: engine timing 101 lol im not an idiot but maybe im doin somthin wrong i dont think i am but ive been wrong before lol maybe what i think its supposd to be set at is wrong other than timing is there anything else it could be any input would be highly appreciated thanks, john

do a search for how to set your base timing, there could be tons of things causing your stumble, look over your vacuum lines for cracks and that there all hooked up with no leaks. are you throwing any codes?

If the EGR system was not "properly" removed - as in having it turned off in the computer as well as the mechanical parts removed - then it can cause problems as cruise/light throttle RPMs. EGR does not rob any power from the engine though, but will improve gas mileage. I'd recommend reinstalling it and making it functional. It will probably solve a few problems for you, and improve fuel mileage to boot.

If the AIR system is removed and the cat converter is not, then sometimes the cat will plug up, which will cause runnning and drivebility problems. The AIR system also does not rob any power from the engine - it just supplies fresh air into the cat converter to help it warm up faster when the engine is started cold. Without the AIR system, the cat will eventually become clogged because of how inefficiently it works when the cat is cold. You either have to reinstall the AIR system if you keep the cat, or remove the AIR and cat together to avoid/remedy this problem.