between cold and warm the car gets pretty bad hesitation with light trottle once warm it is almost gone. also when dead cold i have a missfire seems like. i have done alot to try and fix this. egr,egr solinoid,tps,coolant sensor,o2 sensor,heads redone with new springs and seals with valve grinding,throttle bodys sent out to be rebushed,intalled and in sync.adjusted pressure regulator and it seemed to help with more pressure when cold,but then when it warms up it does it?also did the standard cap,rotor,wires, and plugs. i think this is a common problem with this motor. someone posted a question about this and no one answerd him. any one that has had this happen to them and know what it is, please help.im going trying to figure this out. i'd like to add that i also put a new distributor in. seems that the timeing under light throttle seems to drop back a hair and then advance. could this be the knock sensor doing this being that it is the origonal sensor with probaly origonal coolant for 25 years and all gumed up and not reading correctly. i know that it is not pinging unless slightly to where i cant even hear it. i have the base timming set to factory spec at 6*btdc. any type of input would be appreciated. thanks in advance

 

o.k. figured it out!! gm issued a tsb about this problem and had a fix by installing a new egr valve part number not orginal and a new updated prom to solve this problem... any one else who has this problem with the 305 crossfire, cap off the vacuum port for the egr valve and if the problem goes away, the fix is what was metioned above. however with the age of the motor, these updated parts are no longer availible through gm or aftermarket. my thought is to run the car without egr, just leaving the valve on and not running vacuum to it. does anyone know if this will do harm to the intake or egr valve or do any harm if ran for awhile this way for awhile??

 

Just wanted to update. i found a prom chip from an 82 vette and that took care of it.the egr was bought at the stealership.

 

Any upates?