Went to the track last night, and my last run was a little strange. I only ran .1 slower in time, but trapped 5 mph less than my other runs. Car just didn't get mph on the top end like it had been.
SINCE that run, car's been acting funny. It has started surging after you come off throttle and put it into neutral. Started doing it in the staging lanes so I left and quit for the night.
It's still doing it today. When you start it it finds idle fine, and turning AC just moves it to a higher rpm. But it's after putting it in gear and moving, then putting the clutch back in, it starts surging, and doesn't want to stop. With the AC on it's worse, it surges a lot.
If you've got the AC on and come to a stop, it surges like crazy down to like 200-300 rpm, and the oil pressure drops with it as well, then swings back up. If you flip the AC off it stops and comes back to idle.
Anyone have any ideas of stuff I should check? Or what could be causing it?

 

Any ideas? I'm thinking possible bent pushrod, I hit the limiter in 3rd going across the traps a few times, so it's possible. I'm pulling the covers this weekend to check.