Hey guys, first I would like to say thanks for all the help without having join. Today I am stumped with my 1999 4x4. For the last 2 months during warmer weather (Augusta, Georgia) my blazer runs perfectly fine until it doesn’t. For 5-10 miles it’s fine and then it shuts off. Usually starts right back up and gets me where I need to go and at times it runs 50 yards and shuts off. At times it runs fine and won’t restart for 15-20 after running in the store. After 15-20 minutes it runs fine to get me home. I have replaced the ICM(grease applied multiple types), MAP, Crank and Cam sensors(codes on both), cap, rotor, low temp thermostat(160), plugs, wires, cleaned intake, throttle body, AIC, mass air, every electrical connection I can get my hands on and nothing seems to work. Only codes I have pulled has been crank sensor, cam sensor and a crank to cam correlation. I have read similar post on here but never a direct cause unless I missed it. I have tried all testing that I have found for the ignition switch, ICM, and coil and it all seems fine. Fuel pressure at idle is 50-52 constant. I have also replaced the fuel filter and the EGR valve.The vehicle stalls while at idle and while driving/accelerating. All help welcomed and appreciated.

 

Well, I can tell you first . my expertise is limited, But I am a big car guy, hands on, not afraid to tackle anything and have done alot etc, just not with s10 blazers. and my blazeer is a 91 not your gen, but...

That said, my new to me 1991 S10 Blazer had a lot of what sounds like the same problems, I went to my expert and with confidence he said, I have seen and heard and felt this before, the symptoms sound and feel - fuel related but often he has found that even thorugh it seems that way, it ls often the electronic module in the distributor , it starts to "go wonky" and does not fail completely.

For 140 bucks I replaced the distributor 9full price no shopping around at auto zone, i was in a hurry) Problem solved!!

I probably would not have offered this up as a fix, because I am not a fan of just throwing parts at things, and I do not know all of your other details that may lean you away from trying this but ,, there you go,,,,just trying to help
..
Also I see that no one else chimed in,,,

Funny too, I forgot to take my timing light the day I fixed it , ( it was stored at a friends house at the time), so I carefully "timed the old distributor orientation" with a sctatch on the firewall, that lined up looking across the top of 2 sparkplug wireds on the cap. Runs so good I have never checked the timing since! LOL

I would like to know what happened for you and what you ended up finding and fixing, thanks and good luck, Tom

 

Thank you for your response and experience. Before I read you’re response I changed out the distributor. Luckily for me throwing parts isn’t an issue since I have another blazer at home that was low mileage and has a lot of new parts. Unfortunately it was totaled about a year ago. After hours of tinkering I come to the conclusion I needed a new ECM. As a last result the night before last I took all the connections loose to the ECM and was going to clean everything. I noticed that all the colored covers that keep the wires separated and in place were broken and stuck inside the connection ports. I dug all the broken pieces out with small screwdrivers and picks and cleaned everything well. I noticed a couple wires that’s that had “backed out” of the slot in provided in the plug. Chased down their location and one was the tach signal wire (tach was not reading) and the other was for the camshaft sensor circuit. Can’t remember if it was high or low circuit. Yesterday I made a trip to the salvage yard and got new colored wire covers, again cleaned everything good and put everything back in place. I now have a tachometer, and no codes. After driving around 50 miles or so, no codes have popped up. I hope this has been the issue. I’ve had this baby hooked up to 4 different scanners and their have only been 4 codes. The 3 listed in the original post and I did happen get the high current to the ICM the other night after starting the thread. I’d like to thank everyone involved in this forum, even if they haven’t helped with my post, I have learned a lot just reading everyday on here.