Running badly until at operating temperature

Asked by rayhendrix Mar 22, 2018 at 09:38 AM about the 2007 GMC Sierra 1500 Work Truck

Question type: Maintenance & Repair

I have a 2007 GMC Sierra with a 4.8 liter engine. When I
start the vehicle it idles fine then after a few it drops and
seems to skip.... if it is cold outside it will run fine but once
it gets a little warm it starts running terrible loses power
and spits and sputters but once it reaches normal
operating temperature it seems to run fine... check engine
light is on and when driving even after warmed up it will
flash and then will stay lite then flash etc.... I have
checked codes at oriellys and have replaced the cam
shaft positioning sensor ,the number 4 coil pack, the
plugs and wires and still no change... I have also cleaned
the throttle body and I am at a stand still as to what to do.
Any help would greatly be appreciated

4 Answers

2,460

Hi rayhendrix, What codes were retrieved? After you replaced the above noted parts were the codes cleared? and then no dash warning light? The service engine soon light is alerting you to problems detected by the ECM. Starting point for assisting you are the codes in the order they are displayed. regards

Jack I now can’t get a reader to read the codes... I think the connection port is messed up.... so now I’m not sure what to do... the check engine light is still on and then blinks while driving then it stays on for a time then starts blinking again

2,460

Hi Ray...Try this if you have, or have access to a OBDII code reader. Hook up the code reader to the under dash data port. Turn the ignition switch to on (do not start the engine) Observe the display output to see if the tool is communicating with the diagnostic computer. If the code tool has a connection it will confirm this by displaying codes with a red light indicating detected faults or no codes displayed with a green light indicating no problems were registered. Your flashing service engine soon light indicates a catalytic converter-damaging condition is occurring. Usually you will be able to feel a noticeable difference in the way your vehicle is running and should not drive the vehicle until the condition is diagnosed and repaired...otherwise an expensive catalytic converter replacement may be necessary.

2,460

There are many reasons why the service engine light may blink on. These reasons can range from quick and inexpensive fixes to extensive and costly repairs. Some of the most common culprits behind a blinking engine light are as follows: Ignition coil has failed Fuel injector has failed Engine computer has failed Spark plug Spark plug wire Bad engine valves

Your Answer:

Sierra 1500

Looking for a Used Sierra 1500 in your area?

CarGurus has 67,786 nationwide Sierra 1500 listings starting at $1,400.

ZIP:

Own this car?

Share your experience with others.

2007 GMC Sierra 1500

Review another car

CarGurus Experts

  • #1
    yetilikesbeer
    Reputation
    12,860
  • #2
    dragonflyoffshore
    Reputation
    11,810
  • #3
    John Saffrahn
    Reputation
    11,750
View All

Know more, shop wisely

Search

Related Models For Sale

Used Chevrolet Silverado 1500
4,306 Great Deals out of 116,439 listings starting at $1,500
Used Ford F-150
6,443 Great Deals out of 165,225 listings starting at $1,000
Used GMC Sierra 2500HD
517 Great Deals out of 21,235 listings starting at $3,495
Used Toyota Tundra
1,015 Great Deals out of 25,535 listings starting at $3,900
Used Chevrolet Silverado 2500HD
1,060 Great Deals out of 37,925 listings starting at $2,995
Used GMC Yukon
723 Great Deals out of 12,412 listings starting at $1,998
Used Toyota Tacoma
2,129 Great Deals out of 50,921 listings starting at $4,995
Used Dodge RAM 1500
73 Great Deals out of 1,623 listings starting at $1,500
Used Ford F-250 Super Duty
1,301 Great Deals out of 50,654 listings starting at $1,985
Used Chevrolet Tahoe
1,411 Great Deals out of 29,060 listings starting at $1,550
Used GMC Canyon
338 Great Deals out of 12,008 listings starting at $4,995
Used Chevrolet Corvette
800 Great Deals out of 13,039 listings starting at $6,800

Used Cars for Sale

2025 GMC Sierra 1500 For Sale
5 Great Deals out of 37,301 listings starting at $29,590
2024 GMC Sierra 1500 For Sale
232 Great Deals out of 9,488 listings starting at $29,310
2023 GMC Sierra 1500 For Sale
235 Great Deals out of 3,000 listings starting at $26,911
2022 GMC Sierra 1500 For Sale
163 Great Deals out of 1,925 listings starting at $22,000
2021 GMC Sierra 1500 For Sale
297 Great Deals out of 3,513 listings starting at $19,800

Content submitted by Users is not endorsed by CarGurus, does not express the opinions of CarGurus, and should not be considered reviewed, screened, or approved by CarGurus. Please refer to CarGurus Terms of Use. Content will be removed if CarGurus becomes aware that it violates our policies.