Truck starts and runs great but will suddenly die while driving.

Tiny
DLBUTLER01
  • MEMBER
  • 2001 GMC SONOMA
  • 2.2L
  • 4 CYL
  • RWD
  • AUTOMATIC
Sometimes it runs great, for weeks at a time even, but sometimes it won't go more than a few miles before it dies without any warning, like it isn't getting any fuel. Always fires right back up. Usually happens when fuel is low, but has happened when full. Had codes pulled, fuel mixture is rich. We have replaced the fuel filter and checked all relays and fuses, fuel lines, vacuum lines, fuel pump does come on and fuel pressure is good. Any suggestions?
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Wednesday, April 2nd, 2014 AT 2:06 PM

7 Replies

Tiny
KNOWLEDGE IS POWER
  • EXPERT
If the fuel mixture is Rich that means you have unburned fuel going into the exhaust. That means you're getting plenty of fuel you're just not burning it all. Have you checked your spark plugs and wires, it may be time for a tuneup.
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Wednesday, April 2nd, 2014 AT 3:40 PM
Tiny
DLBUTLER01
  • MEMBER
Yes. We have done a complete tune up.
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Wednesday, April 2nd, 2014 AT 3:45 PM
Tiny
KNOWLEDGE IS POWER
  • EXPERT
Okay, then it could be that your catalytic converters are losing their efficiency and they are causing the engine computer to lean out the fuel mixture at times causing your engine to shut down. You might also have a fuel injector that's leaking fuel into a combustion chamber when it's not supposed to. Either way I'm sure that the engine computer is shutting down the engine due to a rich fuel mixture
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Wednesday, April 2nd, 2014 AT 3:51 PM
Tiny
DLBUTLER01
  • MEMBER
We had the codes pulled again today. We got p0141, p0178, and p0179. We found the HO2S in the manual but the other 2 codes aren't on the list and cannot find anything about the fuel composition sensor in the manual either?
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Friday, April 4th, 2014 AT 5:15 PM
Tiny
KNOWLEDGE IS POWER
  • EXPERT
The fuel composition sensor is inline in the fuel line on the frame rail. Check it for power at the plug with the key on engine off. If it has power either the sensor is bad or there's wire damage in the harness. Look at the wires for chafes or breaks first. The 02 sensor heater one means the 02 sensor is bad
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Friday, April 4th, 2014 AT 5:31 PM
Tiny
DLBUTLER01
  • MEMBER
Thank-you!
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Friday, April 4th, 2014 AT 6:42 PM
Tiny
KNOWLEDGE IS POWER
  • EXPERT
You're very welcome let me know if I can help some more
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Saturday, April 5th, 2014 AT 6:53 AM

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