I know this is an old post but,Mine has been stumbling like hell for over a year now and hardly goes when cold,i have to let it run and warm up,then turn it off,let it sit for 5-10 mins,then start it bk up,Then it runs fine,Sometimes it will stumble into 2nd gear and feel like its jumping in n out of overdrive at 45mph or at 70mph,but most the time after doin that procedure upon starting it,it runs just fine.But i just replaced the Camshaft position sensor n its running like new.I bought anew disty but dont have time to replace the whole thing so i just swapped the cam sensor for now. Oh and mine is a 2000 4.3 2door 2w.d. s10 blazer LS model,139K right now.
But my reason for posting on this post is this:THAT CRANK AND CAM RELEARN PROCEDURE THAT COSTS 100.00 N UP? I READ ON A POST I CAME ACROSS ON GOOGLE MONTHS AGO UPON MY ON AGAIN AND OFF AGAIN RESEARCHING OF MY ENGINE ISSUE,THE POST MENTIONED THAT RELEARN THING CONCERNING THE CRANK N CAM SENSOR REPLACEMENT. If i remember rite,It said you had to warm it up,then drive quarter throttle upto 45mph,then coast down to 10mph,Then accelerate upto 50mph at half throttle then let off and coast down to 10mph,Then accelerate back to 50mph at 3/4 throttle,then once again coast back down to 10 mph,Then accelerate back to 50mph at 1/4-1/3 throttle like you would driven normally,THEN ONCE YOU HIT 50MPH,HIT THE BRAKES,COME TO COMPLETE STOP,PUT IT IN PARK,SHUT IT OFF.WAIT 5 MINS,RESTART IT AND THROW IT DRIVE,AND DRIVE OFF NORMALLY.AND AFTER 20 OR SO RESTARTS AND NORMAL DRIVEN,YOU`LL OF DONE THE SAMETHING THAT OVER PRICED FRGGN GMC MONEY MAKER MACHINE PROCEDURE WILL DO.In these times and most of us out of work,I`d rather spend 15-20mins at night when the roads are dead doin this procedure,Then spend 100.00+ i dont have on a gmc machine doin the same thing.thanks and god bless america!!! KEEP IT AMERICAN AND KEEP IT AMERICAN INGENUITY!!!!

 

Interesting read... so if I was going to replace the distrib in my 98 blazer , what is the good Distrib to buy or is autozone one good enough?

 

Well this all sounds too familiar. Only difference is I traced the misfire to one cylinder. but as "Swartlkk" mentioned before,maybe the wear on the gear favors that cylinder. I swear it was #6 cylinder before that was missing.

 

How do you tell if you have a second design 4.3 vortec? This has me interested.