Help! RMP irregular

[MARCUS VETTE]

Greetings to all.

I’ve got a small problem. My Corvette is functioning well but there seems to be some kind of irregularity with the motor. When it runs idle the RPM shows 6, then 5, then 7 only to come back to 6?? When the car is running at about 100 KM/h, the RPM shows 20, then 19, then 21 only to return to 20. I’ve tried to locate a leak in the plenum with a break cleaner and found nothing sor far...

Any ideas on what to look for next?

 

[TedC]

Can you feel the RPMs changing? I would check out the TPS. Voltage should be checked at idle and WOT. Look for a smooth increase and decrease in voltages between the two positions. On my first vette (1988 L98) I washed down the engine and some water got into the TPS. RPMs would not hold steady. New TPS solved that self inflicted issue. I busted apart the old TPS to find it coated with moisture.

 

[MARCUS VETTE]

Can you feel the RPMs changing? I would check out the TPS. Voltage should be checked at idle and WOT. Look for a smooth increase and decrease in voltages between the two positions. On my first vette (1988 L98) I washed down the engine and some water got into the TPS. RPMs would not hold steady. New TPS solved that self inflicted issue. I busted apart the old TPS to find it coated with moisture.

Hi, I don't feel RPM changing when I run @ 100/KM but I see it changing. On idle, I can hear the engine change RPMs and I can feel it, like vroom down and vroom up!