Hello All,
I've got a 1989 S10 Blazer 4x4, 4.3L, auto, TBI, with approx. 175K miles on it. Last week, my wife, on her way to work, ran over a rock. Since then, the engine has developed a miss. I'm not saying the cause of the miss was hitting a rock, but I thought it might be relevant. The miss is especially noticeable under a load. I have tested the coil and distributor pickup, both are OK. The vacuum tube where the PVC valve attaches to the bottom ot the TBI was clogged. Cleaned that and now have vacuum there. Replaced the PVC valve and air cleaner just because it was time. This week I'll replace the plugs, check plug wires, and throw a bottle of Techron in the tank. Nothing so far has eliminated the miss. I need help with this. What is the next thing(s) I should be checking? EGR? IAC? Would LOW back pressure cause this? (I found the muffler was loose where it attaches to the cat.) By the way, there is no service engine light illuminated (bulb works). I have not checked for codes because of this. Any help appreciated and welcome. TIA
Leyton at Tahoe