I have a 2008 sierra 1500, code p0300 it went from running great to shit in one second any ideas? Have replaced crank and cam sensor

5

Asked by Apr 09, 2017 at 01:47 PM about the 2008 GMC Sierra 1500 SLT Ext. Cab

Question type: Maintenance & Repair

I was driving at 50k or 30 miles per hour on dry road, while cruising the truck went from running great to shit in one second magic code says P0300 random multiple misfires and by the way it feels it is hitting all 8 cylinders, truck runs really rough and seems to be sending gas out the tailpipe as it leaves stains on the garage floor, have replaced the crank and cam sensors, getting 60PSI gas pressure and just noticed the battery may be weak, had headlight on for 5 min and would not start so will be replacing that today, the truck runs so shitty I will not take it out of the garage for fear of breaking something else

3 Answers

73,155

P0300 GMC - Cylinder Misfire Detected Random Cylinders...Possible causes; Faulty spark plug (s), Faulty ignition coil (s), Clogged or faulty fuel injector (s), Intake air leak, Fuel injectors harness is open or shorted, Fuel Injectors circuit poor electrical connection, Ignition coils harness is open or shorted, Ignition coils circuit poor electrical connection, Insufficient cylinders compression, Incorrect fuel pressure...The P0300 code means that a cylinder(s) is misfiring or is randomly misfiring. Start by checking for intake leaks, intake gaskets are common caused of multi-cylinder misfiring. If no leak are found the next step is to replace the spark plugs. If the problem persist more tests needs to be done to diagnose problem...Also check this out... https://youtu.be/QdWd68bVm30

5

so in the end all that was wrong with the truck is a broken exhaust valve spring on the number 2 cylinder and the computer tried it's best to fix it thus taking all the remaining cylinders down too as it ran really bad and spitting gas out of tailpipes

73,155

That would cause the misfire code. Thanks for following threw to let me know what the problem was.

Your Answer

Sierra 1500

Looking for a Used Sierra 1500 in your area?

CarGurus has 67,485 nationwide Sierra 1500 listings starting at $1,350.

ZIP:

GMC Sierra 1500 Experts

  • #1
    dragonflyoffshore
    Reputation
    5,300
  • #2
    John Saffrahn
    Reputation
    3,670
  • #3
    Glenn Clingenpeel
    Reputation
    3,350
View All

Related Models For Sale

Used Chevrolet Silverado 1500
2,164 Great Deals out of 181,160 listings starting at $1,900
Used Ford F-150
2,175 Great Deals out of 181,305 listings starting at $1,000
Used GMC Sierra 2500HD
111 Great Deals out of 13,150 listings starting at $4,475
Used Toyota Tundra
446 Great Deals out of 33,541 listings starting at $1,999
Used Dodge Ram 1500
399 Great Deals out of 10,733 listings starting at $1,500
Used Toyota Tacoma
580 Great Deals out of 41,994 listings starting at $2,995
Used Chevrolet Silverado 2500HD
315 Great Deals out of 29,277 listings starting at $2,650
Used GMC Yukon
431 Great Deals out of 20,905 listings starting at $2,495
Used Chevrolet Tahoe
644 Great Deals out of 37,398 listings starting at $1,800
Used Ford F-250 Super Duty
352 Great Deals out of 43,469 listings starting at $975
Used Chevrolet Colorado
265 Great Deals out of 29,811 listings starting at $2,300
Used GMC Canyon
120 Great Deals out of 12,453 listings starting at $3,299
Used Nissan Titan
207 Great Deals out of 19,498 listings starting at $2,300

Used Cars For Sale

2013 GMC Sierra 1500 SLT Ext. Cab For Sale
1 listings starting at $32,987

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.