Misfire

10

Asked by Jun 05, 2016 at 02:53 AM about the 2004 Chevrolet Silverado 1500 Z71 Ext Cab Short Bed 4WD

Question type: Maintenance & Repair

I have a problem. My 2004 Chevy Silverado will
idle fine for about 30 seconds then all the sudden
my 6th cylinder only will start to misfire. I have
changed my Mass Air Flow sensor, switched out
the coil, switched out the spark plug and wire,
switched out fuel injectors, cleaned out fuel rails,
checked for fuel pressure (it's fine), and even
changed out my downstream O2 sensor in Bank 2.
If I turn the truck off and start it, it will idle just fine
and then again after about 30 seconds of idling it
will start to misfire in only the 6th cylinder. I need
some advice. Any and all help is appreciated!

6 Answers

254,665

What was the condition of the spark plug on cylinder #6? If you replaced the ignition and fuel injectors, the next step would be to do a leak down and cylinder pressure test to see if that #6 cylinder is lower than the other cylinders. Meaning a faulty head gasket or a valve problem. Good luck.

73,845

Should do a compression test on the cylinder, should be around 150 psi. and no lower than 120.

52,125

I agree with Rowefast, you either have a compression problem or an intake manifold leak at #6.

10

Spark plug in the 6th cylinder was just fine. It didn't seem wet like it was getting flooded or anything. We checked the compression in the 6th cylinder that misfires and compression was just fine.

10

Also if I put it in gear right after I start it, it won't misfire but it still seems to run sluggish. Thanks again for yalls help.

73,845

Sounds like you now have to dig deeper into the problem. Ideas I have at this time would be to check the power running to the coil, inspect the wire, check the voltage once she starts to miss-fire, make sure the ground are good. Also you may want to do a fuel bleed down test by hooking up a fuel pressure gauge to the Schrader valve up located up on the intake. Build up fuel pressure by cycling the key on, off, until fuel pressure builds up, should be 56 to 63 lbs. Turn the key off and watch the gauge, it should not drop in pressure more than 5 lbs. in 3 minutes. If it does, this indicates a leaky injector, line, or fuel regulator.

Your Answer

Silverado 1500

Looking for a Used Silverado 1500 in your area?

CarGurus has 165,860 nationwide Silverado 1500 listings starting at $1,900.

ZIP:

Chevrolet Silverado 1500 Experts

  • #1
    John Carson
    Reputation
    2,480
  • #2
    Rowefast
    Reputation
    1,980
  • #3
    Andrew Olsen
    Reputation
    1,700
View All

Related Models For Sale

Used GMC Sierra 1500
857 Great Deals out of 65,105 listings starting at $2,495
Used Ford F-150
2,287 Great Deals out of 183,832 listings starting at $699
Used Chevrolet Silverado 2500HD
309 Great Deals out of 28,952 listings starting at $3,550
Used Dodge Ram 1500
345 Great Deals out of 10,852 listings starting at $1,500
Used Toyota Tundra
425 Great Deals out of 32,055 listings starting at $1,999
Used Toyota Tacoma
632 Great Deals out of 42,613 listings starting at $1,500
Used Chevrolet Tahoe
672 Great Deals out of 39,472 listings starting at $1,000
Used Chevrolet Colorado
268 Great Deals out of 31,396 listings starting at $1,995
Used Ford F-250 Super Duty
351 Great Deals out of 44,655 listings starting at $1,799
Used Chevrolet Silverado 1500HD
10 Great Deals out of 282 listings starting at $3,500
Used Chevrolet Silverado 2500
6 Great Deals out of 252 listings starting at $2,900
Used GMC Sierra 2500HD
115 Great Deals out of 13,415 listings starting at $3,875
Used Ford Mustang
674 Great Deals out of 37,864 listings starting at $895

Used Cars For Sale

2017 Chevrolet Silverado 1500 For Sale
185 Great Deals out of 72,211 listings starting at $20,998
2016 Chevrolet Silverado 1500 For Sale
232 Great Deals out of 6,705 listings starting at $17,422
2015 Chevrolet Silverado 1500 For Sale
313 Great Deals out of 10,840 listings starting at $12,950
2014 Chevrolet Silverado 1500 For Sale
342 Great Deals out of 12,966 listings starting at $9,500
2013 Chevrolet Silverado 1500 For Sale
167 Great Deals out of 5,289 listings starting at $8,981

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.