really awful
Typical Repair Cost:
No data
Average Mileage:
179,506 miles
Total Complaints:
2 complaints

Most Common Solutions:

  1. not sure (2 reports)
2003 GMC Sierra 1500 engine problems

engine problem

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2003 GMC Sierra 1500 Owner Comments

problem #2

Sep 012016

Sierra 1500 SLT 4.8L V8

  • Automatic transmission
  • 125,000 miles


Nothing to say, this has happened almost every day for 7 months. Multiple times per day.

Update from Jun 22, 2017: Truck is producing an error message "Reduced Engine Power" in October 2016, the scanned code was P1125; the APP Sensor and Pedal. Component was replaced in October 2016 by Dick Norris Buick GMC Palm Harbor. R.E.P Warning still displays, and engine continues to lose power despite repairs. Truck was taken to Dick Norris Buick GMC Palm Harbor a second time to find out why their repair was ineffective.

Their mechanics stated the following: • Throttle Body (Connector / throttle wire is damaged) According to GMC this component is not original • Oxygen Sensor needs replacement. • Transmission range Switch. I'm told this isn't a critical issue.

Original Quote 11/1/2016 $688.20 - Throttle Body and Oxygen Sensor replacement Primary Issue: Reduced Engine Power - Throttle Body is the new hypothesis for this malfunction. After inspection – Mechanic re-quoted work to replace Throttle Body / o2 Sensors at $ A/C Influx system. $1491.53

3/20: Work Completed: Throttle Body / Connector wire replaced. $580.00 2 o2 Sensors replaced. Left side of vehicle – $160.00


- , Oldsmar, FL, US

problem #1

Nov 212014

Sierra 1500 5.3L

  • Automatic transmission
  • 234,013 miles

I bought this vehicle apprx 1 1/2 yrs ago. Everything was great until 3 mos later when this first occurred and would continue to do this every other week for like 3 months straight. Then it worked good with no problems for like 3 months, then started up again but less frequently, maybe once a month after that. Sometimes I'll go 2 months and all is good.

The last time this happened was yesterday on my way to work. Luckily I live & work in a pretty regular to lite traffic flow area, mostly country road driving, but I am afraid this will happen when I am in Orlando, Fl as I live like an hour away and we travel there on weekends at times and the traffic is heavy all around, 3, 4 lanes highways and if I am caught in a center lane and this happens, I'm screwed as I have no acceleration power whatsoever. This could potentially be fatal for us and other people involved. I would absolutely hate for something to happen to me, my wife, or anyone else for that matter

Any suggestions would be greatly appreciated. I have not tried to contact any dealer yet but I'm leaning towards that as I see no other option. Maybe there is a recall on this but not sure as I really cannot afford the out of pocket repair on this. Also, how does one go about seeing if there are any recalls that are covered and still might be pending for a vehicle, or maybe had been performed prior to my ownership as this truck was a corporate vehicle prior to me purchasing it. So thanks for any input on this matter....

- , Sumterville, FL, USA

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