I have a 1995 Jimmy. I recently had to put a new spider (fuel injector) in it because my gas was mixing with my oil. After I got that fixed, it continued to spit and sputter while idling. I was told it was the EGR valve building up with soot. I replaced that but it continued. I was then told it was the catalytic convertor, so my mechanic took it off to replace it and when the entire exhaust was off, it’s still spitting and sputtering. It’s putting off an “egg” smell like an exhaust leak and if you put your hand to the tailpipe, it will suck your hand into it. My SES light is on but it keeps coming up the O2 sensor. I was told it’s coming up that because of the catalytic convertor being “plugged”. I am getting about 8 mpg. I was told there must be a vaccum problem somewhere. Any suggestions?
Check for a stretched/jumped timing chain.