OK.. 97 Blazer, 4.3, 2dr, 2wd, auto. 127k miles.
Following symptoms: Hard starting - must crank for 4-6 seconds, wait, crank agian, then it starts. Sometimes have to apply a bit of throgtle to get it to start. Rough idle, first 2-3 minutes of running. Gets better. But at idle even when temp gauge gets to normal, still rough.
"Soot" on the end of tailpipe.
P0300 multiple random misfires, occasionally SES light comes on for 1 driving cycle. Had it read at Autozone.
Recent things done: Was getting a misfire on cyl 5 & 6. "Injector Service", PCV Valve, fuel filter, spark plugs, distributor cap, rotor. 25000 miles ago new fuel pump - old one had gotten noisy and then stopped working. No noise at present time that I can detect.
Thoughts? Coil? Low fuel pressure?
It runs fine going down the freeway. The roughness is sitting at idle at a traffic light, or foot on brake waiting in line. If I put it in N it is somewhat better but still not idling smoothly.
Would like some idea before throwing more $ at it.