Long story short. 1990 c1500 rwd 5.7. Recently my truck died on road while driving. Always ran rich before and sucked lots of gas but still got me there. Rebuilt TBI with Diaphragm for regulator etc. Replaced temp sensor in manifold, also new O2. After this the idle surges up and down and almost dies. If i rev the throttle it runs fine. Timing is good. Possible MAP sensor? or IAC? Just also had new stock exhaust system put on. But it ran awhile before this problem. Ok so not so short. This is a 5 speed manual tranny truck totally stock. Any suggestions or laughter would be appreciated!!