Isuzu Forums - Isuzu Enthusiasts Forum - Engine Missing after 2 hours

Got a real weird problem. Only shows up after driving 2 hours or more at high speed on interstate (speed limits are 70MPH down here).

First, specifics - 2001 Isuzu Trooper, 3.5L engine.

Tried fuel, sea foam injector cleaner, fuel filter, air cleaner, and plugs. Sometimes I get code P300 (random misfires), sometimes no codes.

Returning home on a 500 mile drive today it got so bad that had a flashing Check Engine Light and had to pull over, but when I had mechanic check there were no stored codes.

Of course the problem only occurs when I am far from home and on the middle of the interstate.

In trouble shooting I tried putting cold water on the computer to see if it was a heat problem. It appeared to clear up the problem, at least for a little while.

I appears the problem takes longer to show up if I don't run the AC, making me believe it is heat related.

Except - got close to home and stopped in at the mechanics. I had cooled the computer enough to not have problems but when I tried to pull out the engine died. Desperate I pulled the plastic cover off the intake and cooled the ignition control module (ice chips). Worked like a charm.

So now here I am with a difficult to reproduce problem, no trouble codes, and 2 possibilities
1. Bad computer
2. Bad Ignition Control Module

Any suggestions on what to do?

Thought is to replace the ICM first because I assume it is cheaper and see if it fixes the problem.

Problem is that a search of the internet does not find anyone who sells this. Am I calling it by the wrong name or do they not sell them except at the dealer?

Help!