1995 s-10 blazer, 4.3 vortec 4x4. was running fine, came to a stop and truck started sounding like it was about to stall. continued home about 1 mile, truck misfiring and backfiring the whole way. the problem is not so bad when there is no load, its more like a miss. then as soon as you put it in gear it bogs out and bad misfire with some backfire. the ignition control module tested bad so i replaced it. still runs the same. cap, rotor, plugs, wires, fuel filter and fuel pump were replaced about 2 months ago. EGR valve was replaced a little less than a year ago also.

Running out of ideas, could use the help and possibly some good luck!!




Thanks,
Blazin734

 

Have you tested the fuel pressure and leak down rate yet? The CPI engines are known to have FPR problems as well as 'nut kit' (the internal fuel supply and return lines) leaks.

 

Check the rotor again. Just bought a 2000 Blazer for 500 bucks. Wouldnt run and kept backfiring when you cranked it. Found the rotor actually had a blast hole through it where the spark was going to the distributor shaft instead of the cap. Best deal I've had in a long time!

 

having this same problem, replaced the cap, rotor, and spark plugs with brand new ac delco parts. wires are brand new bosch wires. to better explain the issue im having ill start from the beginning. traded my accord for this truck. it needs exhaust from the converter back, it cold starts and runs perfectly fine but after roughly 15 to 20 minutes of driving light or hard it begins to misfire. once it starts misfiring it hesitates horribly and begins to back fire. when i take my foot off the pedal it will idle normal for a minute or so then begins to drop until it almost stalls out then will begin to rev up and come back down to an idle. when i start driving again it will hesitate very bad and backfire and miss. its getting to be to the point where it isnt drivable. just short quick distance driving. ive changed the cap, rotor, spark plugs, wires, cam sensor/pick up and put more thermal paste on the ignition control module but it still gets a little hot. havent gotten around to checking the fuel pressure but will be doing so tomorrow. im almost at my end with this truck so any help would be appriciated! thank you ahead of time.

 

never mind!!!!! replaced the coil and ignition control module and no more backfiring! runs beautifully