Reduced engine power

Tiny
ROSELEESMITH
  • MEMBER
  • 2004 GMC ENVOY
Engine Mechanical problem 6 cyl Four Wheel Drive Automatic 30000 miles

check engine light and reduced engine power light came on, would only go up to 10 miles per hour.
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Thursday, June 3rd, 2010 AT 9:10 PM

18 Replies

Tiny
KEN
  • ADMIN
This is a safety built into the car so it will not damage any components. The first thing we must do is read the codes, here is a guide for that.

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

This will help us see what part of the system is having a problem and then go from there.

Please let us know what happens so it will help others.

Cheers, Ken
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Wednesday, August 23rd, 2017 AT 12:27 PM
Tiny
CRAZYRED
  • MEMBER
  • 2004 GMC ENVOY
  • 6 CYL
  • 4WD
  • AUTOMATIC
  • 92,000 MILES
Engine Performance problem
2004 GMC Envoy 6 cyl Four Wheel Drive Automatic 92000 miles

my car has been acting up it stalls out when on the road stop and go. We had two techs put on computer and stated oxygen sensors were going we replaced both and added some fuel injection cleaner. It will not stay running now and it chugs and is sluggish. It runs very rough and the reduced engine power light is on and also service light on.
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Wednesday, August 23rd, 2017 AT 12:27 PM (Merged)
Tiny
BILLYMAC
  • EXPERT
Have the convertor tested at exhaust shop for backpressure
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Wednesday, August 23rd, 2017 AT 12:27 PM (Merged)
Tiny
MASONFIRECHICK
  • MEMBER
  • 2004 GMC ENVOY
  • 100,000 MILES
Two weeks ago my car lost power to the motor you would push the accelorator and nothing but it was running and check engine light was on we shut engine off and turned back on and start to drive to local auto parts place to have them find out what code was being thrown by computer. We did make it after loosing power again and stopping and starting motor again once there the engine would not start and we could smell fuel and there was a leak nder the car. The guy at the store said the car went into limp mode and would not start again till problem was fixed so we had it towed (two wheel dolly) to house and the car shop on Monday. The shop owner checked the car out and he called us friday and said the accelorator sensor was bad and he had to get one from dealer before he could start the car he never smelled fuel and said there was no leak. We know we have a leak somewhere and we smelled it so did parts guy. But ok he replaced pedal with sensor ($400.00)and got the car to start and then called us back and said the computer threw out 44 codes when hooked up to the machine to see why the check engine light was one again. So they had to check into that and find out what else is wrong with the car it could take three days. Well four days later he called and said I figured it out the wiring harness on top of the fuel tank shorted out thats why we could smell gas and my car should have started on fire but didnt but he had to replace harness and fuel pump was shorted also and at this point the car would e back together in two days and we would be good to go and out bill would be around $1000.00. He didnt work on the car for a few days cause he was sick had a head ache and then locked my keys in car so had to take a new set down and then Saturday (yesterday) he called my husband while at work and said the Main computer is fried he will find a used one and replace it and only charge us his cost no mark ups. My question does any of this sound normal and if the computer threw 44 codes a week ago while in his possession the computer was working right why is it now all of a sudden not working? And if so how much on average does that cost to fix?
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Wednesday, August 23rd, 2017 AT 12:28 PM (Merged)
Tiny
SATURNTECH9
  • EXPERT
It sounds crazy were the 44 code there before the pedal position sensor was replaced? Its hard to say what's going on without know what the oringal code numbers were?The fuel pump being replaced for shorted wires the gas smell etc all sounds fishy. But its hard to say without knowing all the details what was found tested etc.
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Wednesday, August 23rd, 2017 AT 12:28 PM (Merged)
Tiny
MASONFIRECHICK
  • MEMBER
The sensor was replaced first cause the car would not come out of limp mode with out this being fixed according to the mechanic. He then got the car to start and then the check engine light was still on so he hooked it up and said it threw the 44 codes and he said they were for alot of things including electrical and reduced engine power related things and he said it could take three days to figure it out cause they had to rule them all out. Then ha called and said it was the fuel pump pick up were the wire harnes hooks up to fuel pump was charred and he had to replace all of it he did so and then called and said the computer for the car was fried.
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Wednesday, August 23rd, 2017 AT 12:28 PM (Merged)
Tiny
SATURNTECH9
  • EXPERT
If it didn't have the 44 codes before replacing the pedal sensor it doesn't sound right with the story there telling. Do you happen to know the codes it had before the pedal sensor was replaced? Maybe written down somewhere?
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Wednesday, August 23rd, 2017 AT 12:28 PM (Merged)
Tiny
MASONFIRECHICK
  • MEMBER
I dont have the codes I can see if we can get them but I dont know cause if they hiding stuff from us they may not tell us.
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Wednesday, August 23rd, 2017 AT 12:28 PM (Merged)
Tiny
MASONFIRECHICK
  • MEMBER
And the sensor was already replaced so we have been told by others there is nothing we can do its in already so we have to pay but if the computer was threwing codes it was working right he says the computer is fried but it was working fine last week when he had it so if he broke the computer what do we do
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Wednesday, August 23rd, 2017 AT 12:28 PM (Merged)
Tiny
SATURNTECH9
  • EXPERT
Without knowing codes etc before and after the pedal sensor is replaced along with other details its hard to say what's all going on. It all sounds crazy though sounds like a bunch of guessing. From the first set of codes this computer issues etc should have been found. Its like trying to solve a crime without all the clues. Hopefully that will help you understand how its hard to give a answer as to what they might have done wrong or right. But looking from what I have heard so far it doesn't sound right.
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Wednesday, August 23rd, 2017 AT 12:28 PM (Merged)
Tiny
LIONEL CANTRELL
  • MEMBER
  • 2002 GMC ENVOY
  • 6 CYL
  • 4WD
  • AUTOMATIC
  • 14,200 MILES
Computer problem
2002 GMC Envoy 6 cyl Four Wheel Drive Automatic 142, 00 miles

the service engine soon light is now on constantly and then the reduced power light comes on and the engine strugles to maitain highway speed. The rpms evelevate greatly. My certified mechanc has given up. After replacing the accelerator pedal. Thanks, lionel
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Wednesday, August 23rd, 2017 AT 12:28 PM (Merged)
Tiny
HMAC300
  • EXPERT
Check for dirty battery cables, or a bad battery also check for a paritally plugged converter. Low engine vacuum will do it.
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Wednesday, August 23rd, 2017 AT 12:28 PM (Merged)
Tiny
LISH- LISH
  • MEMBER
  • 2003 GMC ENVOY
  • 0.6L
  • 4WD
  • AUTOMATIC
  • 140,000 MILES
I have a envoy xl about a week ago the reduced power light started coming on I had the throttle body replaced and it drove fine until today light coming on again and only allows me to go 5mph what else could it be
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Wednesday, August 23rd, 2017 AT 12:28 PM (Merged)
Tiny
HMAC300
  • EXPERT
Scan for codes first
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Wednesday, August 23rd, 2017 AT 12:28 PM (Merged)
Tiny
WEASELSHOOTER
  • MEMBER
  • 2002 GMC ENVOY
  • 6 CYL
  • 4WD
  • AUTOMATIC
03 GMC Envoy, disconnected battery, removed altenator to access thermostat. Replaced thermostat and reinstalled altenator. First I received unknow driver message and no start; then Envoy starts but won't shift out of park and has both the SES and Reduced Engine Power light.
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Wednesday, August 23rd, 2017 AT 12:28 PM (Merged)
Tiny
WEASELSHOOTER
  • MEMBER
FYI, problem solved; Passlock had to be reprogrammed.
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Wednesday, August 23rd, 2017 AT 12:28 PM (Merged)
Tiny
TIRESTONE
  • MEMBER
  • 2002 GMC ENVOY
  • 4 CYL
  • 2WD
  • AUTOMATIC
  • 140,000 MILES
Engine Mechanical problem
2002 GMC Envoy 4 cyl Two Wheel Drive Automatic 140000 miles

check engine and reduced power comes on, is intermittent. Tested and found tps sensor 2 not working. Replaced tps -2 sensors in the pedal assy as whole assy replaced. Still have an issue.
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Wednesday, August 23rd, 2017 AT 12:28 PM (Merged)
Tiny
JACOBANDNICKOLAS
  • EXPERT
Are you getting power to the sensor?
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Wednesday, August 23rd, 2017 AT 12:28 PM (Merged)

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