1999 Chevy Blazer Multiple Cylinder Misfire
 

Vehicle was running really bad and getting code P0300 (multiple cylinder misfire) and will not start now.
It has spark and I have verified the timing. I have replaced the rotor, distributor cap, wires, plugs, coil, camshaft sensor, and ignition control module. I check the fuel pressure (53 psi) and did a bleed down test for the injectors (kept pressure for 10+ hrs). I tested the voltages to the crank shaft position sensor ( tested ok) also pulled the sensor to check for any material on it (none). I replaced the fuel pump because the pressure was marginal when cranking the engine (also the sending unit was bad), truck eventually started but is still running really bad and is still getting code PO300.

RE: !999 Chevy Blazer Multiple Cylinder Misfire
 

Good grief! Did you read your post after you submitted it? I went and edited it to remove the nonsense that was in it. Must have been a computer glitch.
Anyway, concerning the P0300 code, have you read this threadand this one? Hopefully they will help.

RE: !999 Chevy Blazer Multiple Cylinder Misfire
 

Ya I check out the post and what a mess. i cleaned it up.
I checked out the other posts but they really don't give me any insight to my problem.
I pulled the following info from my scanner in monitor mode.

Engine RPM - 725 to 740
Ignition timing advance - 14 to 16 degrees
Long term fuel trim1 - -18%
Long term fuel trim2 - -18%
Short term fuel trim2 - -8 to -17%
Intake air temp - 80 degrees
Air flow rate - .76 lb
Throttle position - 0%
Oxygen sensor1, Bank1 - .2 to .85v
Oxygen sensor1, Bank2 - .1 to .8v
Oxygen sensor3, Bank2 - .06 to .07v
Load value - 3.1to 3.5%
Coolant temp - 194 degrees
MAP sensor - 10 in hg

RE: !999 Chevy Blazer Multiple Cylinder Misfire
 

The first post Richard linked to runs through the gambit of causes for a P0300 code. You have to be patient and actually read through the entire post for it to do you any good. Dump out early and I would expect someone to say exactly what you have.

Also, the second post is the book procedure for diagnosing it. If you have a scan tool, you should be able to walk down through the diagnostic procedure.

If you have a specific question about one of the procedural steps in the diagnostic chart or about one of the suggestions made in the P0300 mega thread, post up. But BE SPECIFIC!

If you are impatient and simply want someone to fix your truck for you, well, you will not be satisfied with what can be offered on any online forum.

RE: !999 Chevy Blazer Multiple Cylinder Misfire
 

I just realized that this thread is dealing with the same issue you were asking about in your oringinal thread 1999 chevy blazer won't run. To get the best chance of solving a problem, please keep it confined to one thread so people can respond. Double posting is against Forum guidelines. Anybody wishing to reply to this thread, please do so via the link I inserted.
*THREAD LOCKED*