Alrite i have a friend with an 86 iroc camaro with the 305 carb engine. Im finding out if its a HO or not but i dont know rite now. i dont think it will make a dif. So what happens is that when the engine gets to normal operating temp. and you step on the gas it will pull good to about 2500 or 3000 rpm then start bucking and doesnt stop till you let off the gas. He only has a kn filter and flowmaster exhaust if that makes a dif. Hes takin it to a few mechanics and they all said that they could fix it and tried dif. stuff but nothing worked. I have asked around and i was told it could be vacuum lines. Any help would be greatly appreciated.

Thanks

 

start troubleshooting. check the EGR function,
try swapping on another carb to eliminate that.
How do all the plugs look?.... etc.

 

Change your fuel filter, and do a tune up on the ignition system if it hasn't had one in awhile, also check the fuel pressure, and check for vacuum(sp?) leaks.