You guys seem like a well informed bunch. I hope that you can give me some insight. I went back as far as I could in the threads but did not find anything quite like what I'm having a problem with.
I've got a '91 S-10 Blazer with a 4.3 and it's been destroying plugs in about 5-10 minutes (and I'm sure you know what a drag they are to change-center driver side @#$%^&*). It fouls all 6 plugs black, not really oily but they seem wet with gas when I pull them. It doesn't really seem to smoke much but the exhaust has black carbon-like soot at the end. Mechanically the engine seems to work fine. It has about 137,000 miles on it.
I've replaced the coil and ICM, cap, rotor, wires and plugs several times now in the process. I figure it's the fuel injection system or something that controls it (EGR, ECM, regulator, etc.) but I don't really know FI well. I have not been able to get the fuel filter off, it's 10 degrees here right now, and I'm working outside. It doesn't seem like a filter problem though. I've had 4 TBI trucks and have never had a fuel delivery problem before (probably just blind luck).
If it was a carb I'd figure it was running way too rich like the choke was stuck. The last time I got it running I did get a check engine light before it died. Engine starts, runs fast idle for a minute or two then starts missing and running rough then dies. I can't get it anywhere to have it tested because it won't run long enough and I'm getting desperate. I don't find any obvious vacuum leaks.
Has anybody else seen anything like this or have any advice on where to start? I'll probably need to figure out the codes but I'm not sure how without the diagnostic gizmo that plugs in under the dash. I'd be greatly appreciative. It's just a beater but I'd really like to get it running right without replacing stuff blind, like I've been doing... Thanks for whatever assistance you can offer - Russ