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!

 

Anyone have a suggestion? I have heard from research that it could be the ignition misfire sensor

 

try posting this on planetisuzoo.com

they'll give you an answer over their

this site has pretty much been abandoned

 

Thanks. I did not catch that.

I have replaced the ignition misfire sensor and have hopes that has fixed the problem.