I have a 88 runner recently I replace the head gasket do to overheating problems.Everything was fine .But two days later the truck lost power .When I open the hood the manifold was red hot like a racing car brakes.I need to know how to fix it .can someone help me.

 

Your catalytic converter may be clogged up...or something else in your exhaust system.

 

Ditto on the Cat. That may have even been what caused your problems to begin with. If the exhaust can't escape it's gotta go somewhere.

 

I highly doubt its the cat, but you can check it.

Sounds like its running lean as hell. WAY too much oxygen and its running very very hot. I had the same issue with my 87 and it turned out to be my TPS.

 

yeah, overly hot exhaust means its running too lean most likely

 

judging by the fact that you just had the heads off, i'll say that the timing is off.