ICM, ECU? How do I determine which one?

[Nykademus]

Hi folks,

I have been having an intermittent problem with a 97 Lumina that has the 3.1 in it.

I know (now) that there is a common problem with these engines where they will stall when the engine gets up to running temp. It sounds like its either the ICM (ignition control module) or the ECU (brain box)

And, then there is the TCC problem that seems to be common with this engine also.

Is there a way to determine which is going out between the ICM and ECU? I know that I will need to replace one and I just want to replace the right one rather than both.

The engine will not start once it stalls very much anymore, which it was when the issue first showed up.. first it would bog, then it would die and start up and run for a bit until I came to a stop (and die there), now it will not start after it stalls.

One thing that remains common is that it dies when coming to a stop or slowing down for a turn.

Thanks for any help!!

[Nykademus]

A couple of things that I should mention.

The fuel filter and starter have both been replaced (issue caused starter failure).

The car will start fine and run like a dream for about 20 miles and then the issue will show itself, sometimes. It is not consistent and can go a couple of days w/o any issues.. but then when I NEED to be somewhere.....

When it does start to act up you can watch the RPM cut out, and if you switch to neutral and rev it acts like it is not getting any fuel and runs real rough and dies when you let off of the gas.

Not sure what else to include but would gladly answer any questions.

Thank you!!

[Nykademus]

would it help if I said pretty please?