This may sound dumb but, what can I spray over my headers, etc. to check for leaks?

I just changed my driver's side header and collector gaskets, but I am still getting surging at idle and sometimes btwn shifts (M6). Could it be normal because of my cam? It only does it sometimes.

ok, my father told me to use some dishwater soap and just spray it on???

 

I never sprayed anything to test for exhaust leaks. Sometimes you can see a black spot on the head or header that indicates a leak, otherwise I'd just feel around the flange with my hand when the car was cold.

 

I did that last time, but this time I don't see any spots since the gasket change. I think I can still hear a leak somewhere. What I do know is, the idle will rise several hundred rpm--maybe my timing is off?

 

Another thing you could do is take a good length of rubber tubing that's 1/2" in diameter or larger, and hold one end to your ear and the other to the presumed location of an exhaust leak. You'll know real quick if it's there or not.