01 ZR2 Blazer. History:
Picked it up at scrap yard last year for $1200. 150,000 miles on it now.
Kid that had it was dumb. Had a K&N filter on it and it was sucking water with mud through motor. Didn't discover that till now though. Torsion bars maxxed out, 3 in lift in back. Several bolts from plenum missing. Anyways. Never had power my 4 doors did. Intake man started seeping coolant on top 2 weeks ago. Changed gaskets. Somehow a bolt from intake made it into cylinder. Mine were all acounted for in styrofoam that I put them into cuz was afraid of that. No idea where it came from.
Got another motor with 100k on it. This motor has 0300 code and can't get rid of it. 3 different caps and rotors. Old dist had a wobble, put a known good one in it. The old dist with wobble was from motor removed and worked fine then. I have the parts off a 96 Blazer at my disposal plus the old motor removed. I've swapped everything. Wires ,plugs, and even went and bought new. Swapped coil and IM. steady vacuum of 19-20 at idle and 25-27 at about 2500 rpm. No flux in vaccum reading. Ruling out leak from faulty install of gaskets. Swapped injectors with known good. The replacement motor had the MFI on it. Put the old spider in it from 2 motors that were known to be ok. Even tested them out of vehicle to observe spray pattern and all 3 spiders seem good. Only thing not changed is crank sensor. Will this need to be relearned with the replacement motor? Could it be from CPS or no? 1 ground was broke on left head when motor went in, its fixed and soldered before dropping motor in. 3 grounds per side on back of head. Pretty sure didn't miss any.

Any suggestions.

 

I guess no one wants to know what the fix was.

 

I will ask....what was the fix? But not interested in buying.

 

after reading this im very intrested in what the fix was!

 

I am very interested in knowing what the fix was! I have battled the P0300 on and off over the years as many of us have! This is my first post but I have been lurking for quite some time and working on these vehicles over 10 yrs.

Thanks,
Andrew.

 

In my particular case with changing the motor I had to have the crank sensor relearned. I believe it also is a dealer trick from what I heard. It's been flawless since except for the new 02 sensor only lasted 1 year to the day. Had a code for evap but I take a piece of round plastic and drill a pin hole in it and insert in hose just before solenoid on intake. Keep enlarging hole ever so slightly with pin drills till you get it perfect. Also if you have a 96 blazer, the codes can be reset while you are driving and it will NOT clear the monitors. I always did it with mine just before pulling in for inspection. Not sure what years this works on but my son in laws 96 is also the same way. My 01 will not do this. Maybe 97-99 will.