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

232,725

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.

65,675

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

44,665

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.

65,675

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

Add photo

Related Questions

  • Silverado 5.3 L is misfiring 9 answers

    My Silverado has a misfire when a load is put on the motor ie going up a steep grade or hill. Cruising down the highway at 55 mph, transmission in overdrive, the rpm's drop to around 1500 or 1400...

    2000 Chevrolet Silverado 1500 LS Short Bed 2WD

    -

    Maintenance & Repair

  • 1998 Chevy Silverado misfiring rapidly! Help please! 8 answers

    I was driving my truck the other day and it was running fine and all of a sudden it started running extremely rough and misfiring like crazy. It also started running really rich and also gas is lea...

    1999 Chevrolet Silverado 1500 3 Dr STD 4WD Extended Cab SB

    -

    Maintenance & Repair

  • Misfire code 3 answers

    What could keep a brand new spark plug from firing if wires are good spark plug is new and coil is new. 1999 Chevy silverado

    1999 Chevrolet Silverado 1500 3 Dr LS Extended Cab Stepside SB

    -

    Maintenance & Repair

  • misfire on 6 chevy 2011 1 answer

    2011 Chevrolet Silverado 1500 LT Crew Cab

    -

    Maintenance & Repair

  • Misfire 1 answer

    Replaced distributor,distributor cap,spark plugs and wires but still has misfire what could be the problem

    1999 Chevrolet Suburban K1500 4WD

    -

    Maintenance & Repair

Silverado 1500

Looking for a Used Silverado 1500 in your area?

CarGurus has 168,424 nationwide Silverado 1500 listings starting at $1,800.

ZIP:

Search Chevrolet Silverado 1500 Questions

Chevrolet Silverado 1500 Experts

#1 John Carson
John Carson
Reputation 2,110
#2 Rowefast
Rowefast
Reputation 1,790
#3 Silverado_owner_2006
Silverado_owner_2006
Reputation 1,610
View All

Related Models For Sale

Used GMC Sierra 1500
809 Great Deals out of 66,570 listings starting at $1,995
Used Ford F-150
2,243 Great Deals out of 208,468 listings starting at $1,499
Used Dodge Ram 1500
446 Great Deals out of 11,404 listings starting at $1,000
Used Chevrolet Silverado 2500HD
306 Great Deals out of 26,891 listings starting at $1,250
Used Toyota Tundra
473 Great Deals out of 33,648 listings starting at $3,500
Used Toyota Tacoma
501 Great Deals out of 39,439 listings starting at $2,900
Used Chevrolet Tahoe
569 Great Deals out of 27,371 listings starting at $1,500
Used Chevrolet Colorado
226 Great Deals out of 23,565 listings starting at $2,200
Used Ford F-250 Super Duty
343 Great Deals out of 47,460 listings starting at $1,795
Used Chevrolet Silverado 2500
8 Great Deals out of 299 listings starting at $3,000
Used Chevrolet Silverado 1500HD
14 Great Deals out of 263 listings starting at $3,950
Used Ford Mustang
374 Great Deals out of 46,937 listings starting at $1,999

Used Cars For Sale

2017 Chevrolet Silverado 1500 For Sale
42 Great Deals out of 115,018 listings starting at $19,580
2016 Chevrolet Silverado 1500 For Sale
148 Great Deals out of 6,042 listings starting at $18,190
2015 Chevrolet Silverado 1500 For Sale
167 Great Deals out of 7,247 listings starting at $15,888
2014 Chevrolet Silverado 1500 For Sale
271 Great Deals out of 10,346 listings starting at $9,988
2013 Chevrolet Silverado 1500 For Sale
155 Great Deals out of 5,111 listings starting at $7,650