hello ...a pontiac transam gta -89 350tpi . car starts and runs okey until temparature goes up , then it start to goes up end down in rpm , if a turns off it wont starts untill it colds down ...any ide were to start searsing fault......

 

Easiest kind of problem to fix IMO is a no-start. FAR easier than a runs-like-crap.

For an engine to run, all it needs is The Big 3 Ingredients: fuel/air, spark, compression.

Which one goes away?

I'm betting it's not compression; that doesn't go away when hot and return when cool.

That leaves air/fuel, and spark.

Does the throttle open? then it's not air. That leaves fuel and spark.

If it'll start with some starting fluid squirted into the throttle body, even if only for a second or 2, then it has spark, and it's a fuel problem, If that doesn't get it to start, then it's a spark problem.

Did I not say earlier that this is EEEEEEEEZZZZZZY?

My money would be on spark, if I was the betting kind. (I'm not) Specifically, the ignition module. But, don't just jump to that conclusion; do the troubleshooting.