Will big cams give my car a lopy idle?

[Michael P]

Recently bought a 89 N/A Supra from a friend of mine. and everything on the car works great, no check engine light. but it has a very lopy idle. it will jump up and down from 6-800 rpm. and it does this very evenly, and do not miss when you rev the engine.

the person I bought it from said it's always done that because it has aftermarket cams. Just asking to make sure this would in fact cause the lopy idle. I plan on doing a tune up either way.

 

[ballstothewall69]

Hey bud.. what your buddie told you was right. That is the aftermarket cams that make the idol jump. The bigger the cam the slower the lifters open the valves which in turn slows down the idol and makes it choppy.. it also has to do alot with the compression of the motor, and from the way you described it being so consistant whoever did it did everything right.