Rep Power: 0

I have a 92 dx that runs perfectly fine at 120k miles but after it gets warmed up and I put it in Park, the car goes into a rhythmic hesitation like stalling then starting. This only occurs in park or neutral (after warmed up) and before i would turn the headlights on (while in park or neutral) and this would increase the rpms and stop the hesitations but now nothing helps its getting worse.

I was thinking catalytic converter or erg vavle? anyone got any ideas

 
Rep Power: 812

could be a clogged intake air valve like iac or fitv. pretty much any of those things bolted to the intake mani or throttle body should be removed and cleaned.