1997 Chevy Blazer Lack of power/ Stalls/ help

Tiny
ETMAN9
  • MEMBER
  • 1997 CHEVROLET BLAZER
  • 6 CYL
  • 4WD
  • AUTOMATIC
  • 191,000 MILES
I have a 97 Blazer that when travelling up long hills, starts lacking power, engine light flashes, and sometimes stalls out. Once back on level ground, all power returns. I have scanned ECM and codes are P0101 and P0300. I have replaced MAF and done tune up. Fuel pressure holds at 60psi. Has plenty of vacuum. No leaks. Any ideas? This is really stumbling me.
Sunday, February 21st, 2010 AT 6:30 PM

6 Replies

Tiny
2CARPRO JACK
  • MECHANIC
  • 11,533 POSTS
At that mileage you could have a weak injector causing the P0300 (random misfire) and/or a weak fuel pump causing the P0100 (MAF performance). Have you replaced the fuel pump yet? Sometimes they can keep good pressure, but cant maintain volume when needed (going uphill) which can cause a lean condition. Does it ever miss or run poorly other than pulling a long hill? I have even seen partially plugged cat converters do this.
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Monday, February 22nd, 2010 AT 7:25 AM
Tiny
ETMAN9
  • MEMBER
  • 4 POSTS
Fuel pump was replaced around 50,000 miles ago. I have noticed that in the mornings that it takes a moment to start. I put the gauge on it and noticed after sitting for some time, that the pressure drops. I even let it sit overnight with the gauge on it and noticed it read 0 in the morning. The only other times, other than driving uphill, that it acts up are if I try to pass someone. I'm leaning towards pump, but would like a little more insight on what you might think.
Thanks.
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Monday, February 22nd, 2010 AT 5:07 PM
Tiny
2CARPRO JACK
  • MECHANIC
  • 11,533 POSTS
Since you have apressure gauge, I would install it and drive up a hill to see what thepressure does. The bleeding down could be a bad pressure regul;ator. Does thepressure jump up when you rev the engine? If not the reg may be blown, it is under the upper intake plenum
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Monday, February 22nd, 2010 AT 7:55 PM
Tiny
ETMAN9
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  • 4 POSTS
I snapped the throttle and noticed that the pressure dropped then returned. Gonna try the reg and see what happens.
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Monday, February 22nd, 2010 AT 8:03 PM
Tiny
ETMAN9
  • MEMBER
  • 4 POSTS
I tried driving with the gauge on. The pressure stayed at 59-60. Would not go over 60psi. Also didn't act up. Had power, MIL stayed off. Will definately try the reg and let you know what happens. This car has been baffling me for a few weeks.
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Monday, February 22nd, 2010 AT 8:13 PM
Tiny
2CARPRO JACK
  • MECHANIC
  • 11,533 POSTS
Pressure should jump up a few psi when you snap the throttle. This is sounding like a bad/weak pump. Most of the time if the reg is popped it will stay high and not do anything when you rev the engine
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Tuesday, February 23rd, 2010 AT 7:24 AM

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