Chevrolet Repair: Engine light, 1988 chevy 1500, pickup 4x4

Question
Kevin
I have a 1988 chevy 1500 pickup, 4x4, 350 5.7 liter. I have
done a lot of work on it, all myself too to keep costs low.
The biggest things that i have done, both done in the last
two months, is put another (used) transmission in. And i
replaced a piston, it had compression on no higher that 60,
and blow by of 85%. Im pretty sure you know the extent of
the work i had to to do to replace that. Ok, i have it all
together, with no leaks.It runs and idles pretty darn good
now. The only thing that is different is the engine light.
After about 5 miles of driving it comes on, then a minute
later turns off. If turns on and off every 1-5minutes.
Because of how random it is i cant get it checked, do you
have any ideas of what could be causing this? Thanks

Answer
Possibly a loose wire to the engine, possible internal issue, possibly trans issue, could be exhaust, but you might check for codes anyways. Sometimes they get stored even though the light is off. Also view the data stream on a scanner if one is available. A lot od times you can find it there.