Okay…I have an 01 blazer 6 cylinder 4.3. For a while it was missing fairly bad until I had the distributor replaced and the problem went away for about 2 months. Now it seems to have the same problem again so I am wondering if that wasn’t the real problem. Here is what is going on. The tac needle bounces and it feels like the engine is misfiring. When I am driving on the highway sometimes the CEL starts flashing. Sometimes it stops and sometimes it doesn’t. Plus now it feels like when it changes gears it’s lurching. It only does that sometimes. The odd part is there seems to be no distinguishable pattern to the lurching. I think the misfire could be just the timing needs to be adjusted. Any ideas anyone?
@mderouin Timing is not adjustable on that engine
The light flashing means the misfire is severe enough to damage the cat.
Check spark and fuel pressure. That CSFI fuel injection system had some issues, most of which are not difficult to diagnose and repair, for an experienced and competent mechanic, that is.
Check that coil. Sometimes the coil wire would arc against nearby brackets.
Perhaps it’s time for plugs and wires?
those were replaced with the distributor. I am most definitely not the most experienced but small issues I can usually figure out but this one is just over my head. Thanks though, I will tell my mechanic to check it out.