As some know, I've been having a problem with a rough idle when the car is hot. Just wondering whether using a code reader will tell me why, even though my check engine light has never come on.

 

i use what is called a "genesis" that we have at out schools auto shop. i know you dont have access to one, but ive heard they do scans at murrays. call murrays and see if they offer scans for OBD1 vehicals.

 

Thanks for the reply. The purpose of my question was to find out if a code reader would tell me anything, even though my check engine light has never come on. Any thoughts?

 

You don't need a code reader, simply follow the DIY KOEO/KOER self-test procedures using a VOM, test light or CEL indicator to read the codes.....there are codes/failures that will not trigger the CEL + by doing the KOER, you'll test the system real-time...also suggest to do the cylinder balance test described in the link. My 2¢.