I recently bought an 85 Corvette and it seems to have a pretty prominent dead, or flat, spot from just off idle. It only shows up when the engine has been thoroughly cooled down, like overnight. When the engine is warm, it doesn't appear to have the flat spot...I probably wouldn't have even noticed it, but I changed the exhaust yesterday and was revving it to see what it sounded like, lol, and that's when I discovered the dead spot. Just looking for ideas of what, or where, to look...

fwiw, the car doesn't have an issue where it is unmanageable to drive when cold or anything, just has the pronounced off idle spot where if you try to rev up the engine, nothing seems to happen right away, it has to sort of catch up, if that makes sense?

 

I am having the same issue with my '91 Z-28. from an idle say at a stop light, when I ease onto the accelerator it seems there is an intermittant dead spot, the car will hesitate a split second then lunge forward. Common sense tells me the resting position on the throttle position sensor is becoming worn, but I have not replaced it yet to verify. I am curious to see what others have to say on the issue.

 

Mine has a different issue, it seems.

Mine only does it when engine is first started, but still drives ok. Maybe it drives OK because it's a stick shift car? A bad TPS wouldn't only act up when engine is cold.

 

no ideas?