My 93 is vibrating and shuttering after cold starts. It takes a good 4 seconds of cranking to get her goin', and when it gets going there is a breif, strange, grinding skreeching noise. the car vibrates until warm, like Silver. I am going to pull the codes and clean the throttle body asap, but i was wondering how you are supposed to know where the TPS needs to be adjusted to. Thanks in advance.