Give ya 50 for it

 

lol. Sorry for the flame post.

 

Ok, fuel pressure was zero this morning. Added some fuel from a can, it jumped up to 60 psi. Guess a little ice got stuck down there. ??? Anyhow, here is the data you asked for:
The fuel pressure is 50 psi while running and jumps to 60 psi when I hit the throttle quickly, about 1/2 way down like you said then drops back down to 50.


DTC's: started with P0301 and no FF data then, scanned again and got P0300.
FF data:
Fuel Sys 1: CL
Fuel Sys 2: CL
Calc Load: 3.1
ECT: 188.6
STFT B1: -2.3
LTFT B1: 8.6
STFT B2: -14.8
LTFT B2 3.9
MAP 8.9
RPM 1044
Speed 0
MAF 1

 

No fuel pressure: First need to find out if the pump is getting voltage, every time. When the ignition is initially turned to the run position, there must be voltage for ~2 seconds, then drop to zero, on the grey wire. Need to check it at the fuel pump module connector. If you hear the pump motor run with each key cycle, there could be a problem with the pump itself, (attached to the motor).

The misfire is being caused by a rich condition. Either too much fuel, not enough air, or the fuel is not being burned. P0300, (random cylinder misfire) is almost always caused by a fault in the secondary ignition system: plugs, plug wires, distributor cap, rotor, and ignition coil. It can also be caused by low fuel pressure, worn distributor bushings or drive gear, and incorrect camshaft retard.

 

Okeedoke. Thx. A few people have been adamantly insisting that we need to use only Delco parts for the cap/rotor, etc on these Blazers. I used aftermarket, so that will be my next move. As to the pump, that was weird. I think (as stupid as it sounds) that I simply ran out of gas, but I'm not sure. All I know is that when I added another 5 gals from my gas can it worked. The, I took the truck up and filled it at the station, another 13.5 gallons, so it was pretty low.

I'll change the parts and post the results.

 

Ok, bought an AC Delco cap and rotor, installed them this evening and VOILA! Truck runs great! I must say that I have never run into this before and I have been working on cars/trucks for a long time. Does anyone know what the problem is with these aftermarket ignition parts? Just so everyone knows, the parts did function properly after I installed them. They began malfunctioning about 800-1000 miles after installation.

Anyhow, thanks for all the help, Captain, and hope Google picks this thread up soon so someone else might be spared the expense I went through to fix this problem.

 

It helps when we have freeze frame data to look at. P0300 can be a bear to diagnose without it. Having fuel trim numbers tells where to look, and eliminates a whole bunch of stuff.

There are tons of threads here where people have spent hundreds of dollars on parts trying to guess what the problem was. Turns out all they needed was an AC Delco cap & rotor.

Not sure if it's brass terminals, or crappy insulation that causes the problem, but I haven't seen an aftermarket cap make it 50K miles, and haven't seen an AC Delco fail before 100K! The interesting thing is, you can't see a problem, they look fine, and measuring resistance is inconclussive.

Glad that took care of it for you. Keep an eye on that fuel pressure, (and gas gauge)

Thanks for posting back.