milehigreg
Well-known member
Don't give up!
Leave the .44 wrench in the tool box!
I just went through almost two months of troubleshooting mine and we finally found the problem. The beneift is that you will have reduced the number of parts that can fail and leave you stranded by replacing them before they do. You have also learned a lot about your Vette. You WILL figure this out! The fact that it only runs rough at idle leads me to agree with Key West Jack, you might have a small vacuum leak. 
Since you did a smoke test and found nothing, it might point to the EGR valve. If stuck open only a little, it provides an internal vacuum leak which your smoke test wouldn't expose. At off idle, it could be small enough that it doesn't have an effect. Now that this is in the correct thread, GMJunkie is sure to see it and dollars to donuts will opine your problem is the EGR. JUNK, WHERE ARE YOU! Good Luck and keep at it. 
Leave the .44 wrench in the tool box!
I just went through almost two months of troubleshooting mine and we finally found the problem. The beneift is that you will have reduced the number of parts that can fail and leave you stranded by replacing them before they do. You have also learned a lot about your Vette. You WILL figure this out! The fact that it only runs rough at idle leads me to agree with Key West Jack, you might have a small vacuum leak. Since you did a smoke test and found nothing, it might point to the EGR valve. If stuck open only a little, it provides an internal vacuum leak which your smoke test wouldn't expose. At off idle, it could be small enough that it doesn't have an effect. Now that this is in the correct thread, GMJunkie is sure to see it and dollars to donuts will opine your problem is the EGR. JUNK, WHERE ARE YOU! Good Luck and keep at it. 
