I've owned my 2000 Blazer for about a year now. I had to replace the motor, which was about to blow from the previous owners stupid antics.
Sinse the beginning it's had a missing issue. Random missfires, and an attitude of it's own as to when it wants to act up.
I've read all the threads on the dreaded P300 code.
I've repeatedly done the wires,plugs,cap,rotor,MAF sensor, crank sensor, complete distributor, coil w/module, TPS, MFI conversion, New fuel pump/filter, dielectric grease on every plug terminal, I know I'm forgetting to mention something.
Lately I've been getting some lifter ping on acceleration.
So I sent the original motor out to get it rebuilt in case it's the sticking lifter problem.
If I get it back together and it still has gremlins I'm going with HEI ignition and running a carb on top.
Just wanted to see if anyones done it yet and got any helpful suggestions to make it go a little smoother?
I like my blazer and other than the running issue everything is great. I've got to much invested in this blazer to just give it up. I'll make it run right one way or another.

 

i have had similar issue with misfire......and it turns out that in the 4.3 lts W and X egines of s10 blazers,,, the dealer calls for a cr43tsm plug ... make sure that you use the m plugs,,,,or you will have a misfire problem.the aftermarket dealers always seem to push the more common plug ( cr43ts) rather then sell you what you really should have...something to do with the length of the threaded portion of the plug ...the cr43tsm are a bit longer than the rc43ts ...

 

Did you have a knock sensor code? If it was pinging then the computer should have retarded the timing. Pinging is sensed through the knock sensor. It isnt caused by lifters. Sorry.

Have you run a live data scan when it was acting up?