2004 Chevy Blazer P0101 and P0300

MADMECHANICMARK

MEMBER
2004 CHEVROLET BLAZER
6 CYL
4WD
AUTOMATIC
82,000 MILES

2004 chevy blazer started acting up for brief minute then ran fine for another 5 hours or so then lost power and wouldnt go over 20mph. Then after that wouldnt even start. So we replaced wires (which two had melted) plugs, distributor, distributor cap, rotor, coil, maf. We removed the cat and muffler (with it the downstream o2s of course) and still runs rough. Idles fine but no pickup and about 8.5 mpg. Odb says bank 1 lean 0-1g and bank 2 rich 20g. Checked fuel pressure and its fine. We have a couple of ideas but dont know where to go from here. And keeps coming up with p0101 and p0300 codes through all of this. We changed the mass air flow and vacuum lines and put gas treatment and super in the gas.

Sunday, May 30th, 2010 AT 6:27 PM

3 Replies

RASMATAZ

MECHANIC
75,992 POSTS

P0101 MAF sensor -clean it with an approved cleaner

P0300 Random misfires normally caused by vacuum leaks and bad fuel

Check the fuel pressure with a manual gauge. See what happens when you shut the vehicle off. I have seen these SFI engines develop leaks in the fuel lines under the upper intake and shoot raw fuel into one side of the engine. The computer freaks out when it sees the unburnt fuel and tries to compensate. As strange as it sounds raw fuel can create a false lean due to the fact the oxygen is present due to the lack of combustion. Thus a "Lean" mixture. A blown fuel pressure regulator can do the same thing

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Sunday, May 30th, 2010 AT 6:58 PM

APRILREIN

MEMBER
2 POSTS
2001 CHEVROLET BLAZER
6 CYL
4WD
AUTOMATIC
109,000 MILES

I have a code P0101 coming up (among others) when I take vehicle thru inspection, wont pass inspection, just replaced fuel pump and fuel injectors.

Can you tell me what this code means besides the definition on your site? In laymans terms?

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Wednesday, January 23rd, 2019 AT 6:15 PM (Merged)

RASMATAZ