1990 tracker -no start FI fuse?

[rjm]

I replaced the ECU and the truck runs! Obviously the ecu has something more than leaky caps and the suspect zener diode. I want to fix this ecu and keep it as a spare in my boony box. I'm a bit leery of going out on the trails after this event. What can you offer as next component to replace? I'm interested in fixing it myself ( was quite satisfied with my soldering skills - but struggled with the "desoldering" I think this "solder wick" thing maybe helpful. If I can't, then it goes to cardone or other repair house for test/repair. I still find it amazing that it was running perfect and while idling in the garage it just quit!
again -any help is appreciated. As a side note the cold idle is about 2k rpm. Is that a sign of something off or simply an adjustment? once wamned up the idle is about 750 -ish.
Thanks rjm