This is the new to me 1987 4wd 5-speed TV, that I bought with a blown head gasket. Originally a CA van with lots of heat damage under the hood. Brittle wiring, cracked exhaust manifold and downpipe. I just finished the HG replacement and associated repairs to exhaust components, wires and hoses. Took it for a test drive.
It starts and runs well, but every now and then the check engine light will come on for a short while, accompanied by power loss and hesitation. After the light goes off, the engine runs normal again. This repeats itself randomly, regardless of engine temperature.
Before I go down the long check list, I thought I would check here to see if there's a known primary suspect for this kind of behaviour.
Thanks!