I have a '94 LT-1 great car but just developed problem .Runs fine when cold for up to 45minutes then starts surging and running rough at idle and will hardly run when applying throttle. Have replaced coil and ignition module no change . Is it the OPTI-spark unit? there are no codes or check engine light . Need help thanks.

 

Check fuel pressure. Could be weak fuel pump

 

Did you ever figure this out? I'm having the same problem. Thought it was EGR related but replaced both EGR and EGR solonoid and neither fixed it;

 

How come you thought it was the EGR/EGR solenoid?

 

does it start to do it right after youn enter closed loop??? mileage??? my hunch would be opti but dont be hastey with out a proper diag. of your problem !!!![:@]

 

I am having the exact same problem on my 92 LT-1.The car recently had a tune-up including new OPTI spark cap. It does the same thing runs a bit rough at idyl, after 30 minutes if you step on the gas it seems like its not getting fuel and then it stalls.Ichecked for spark when it is not starting and I have spark. Seems likeit isnot getting fuel when hot. If I let it cool off and sit for 30 minutes it starts right up? Any ideaswhy its not getting fuel when hot? Would a fuel pump work okay when its cold and not work when its hot?
Bruce