Been awhile since I been around. Sold my z-28 to Dad a year ago. But now he has a recently developing issue I'm looking for help doctoring. It is still the Lt-1 with vortech S trim running 8lbs boost and other sig line mods.

Once the car is warmed up and not idling higher do to cold start, the idle is low and you have to feather it at the stop light. Keeping the rpm about 1K. On occasion, it dies as you try to take off. You can restart right away and be fine. But you never know when its going to do it. When it tries to die under these circumstances, trying to save it with the throttle yields no noticeable reaction.

The issue has got him in trouble in traffic a few times. I realize this is likely not sufficient detail, but the local shop has been unsuccessful. My old mechanic in Colorado thinks ... EGR sticking ...vacuum leak ....fuel pump. Looking for thoughts.

 

The suggestions from the other mechanic are certainly valid, especially egr - maybe check that and see if it is all coked up and stuck open. I'd also check ignition connectors, the ICM and coil, which can fail or degrade from heat. Clean the MAF sensor. If it is really intermittent, and you can't get it to fail hard, then I would suspect an electrical connection moreso than a component. Like you said though, not easy to diagnose through the internet. Maybe get a scanner on there and see if everything checks in and parameters make sense when it goes into closed loop. See if there are any codes.

 

Pretty much this. Scan it until you can get the car to stall with the scanner running.