Jump to content

Stumped 6.2l

Pmulls870

Recommended Posts

Pmulls870 Enthusiast

Pmulls870

Posted
Posted

I'm hoping one of you guys might be able to point me in the right direction before I go back to the dealership.

 

I have a 2010 Yukon XL Denali with 145000 miles. About 1000 miles ago it threw a cylinder 7 misfire code. Replaced plug, cleared code, didn't come back. 500 miles later, rough idle, no codes. The next day, cylinder 6 misfire. Replace cylinder 6 plug, clear code, code doesn't come back. Rough idle remains. Fire up, warm up truck, take it for a ride down the highway. Check engine light flashes, stabilitrak lights come on. Slow down, all lights go away, try to get up to speed, engine sounds like it's ticking on the even side bank, engine light flashes. Slow back down, light goes away. This happened twice more on my way home always during acceleration. Any idea what my next step might be?

Daryl LBZ Senior Enthusiast

Daryl LBZ

Posted
Posted

Any stored codes? Probably not since it was a flashing engine light. Could be a bad coil pack, plug wire etc...

Pmulls870 Enthusiast

Pmulls870

Posted
  • Author
Posted

Is it strange that it jumped from cylinder 7 to 6? That's the part that is troubling me. Should I be worried about that?

silveradosid Senior Enthusiast

silveradosid

Posted
Posted

buddy had that on his chevy pickup, every time on the highway the cel would come on and back off the power. the fix was to replace cats, the left side was almost plugged and the right side was half plugged

Pmulls870 Enthusiast

Pmulls870

Posted
  • Author
Posted

That's very strange, I would have to check my reader again but I thought I had good flow. Does anyone know of a good way to check on this without tearing the cats off?

Pmulls870 Enthusiast

Pmulls870

Posted
  • Author
Posted

I went out and did a test run out on the highway, the original condition still remains, checked temps in both cats - 20*F outside temp, both cats are running at 1560*F or so. I would think if they were plugged or plugging they would would be running at drastically different temps and I would imagine they should be running higher than that?

Archived

This topic is now archived and is closed to further replies.

Go to topic listing

  • Latest Articles

  • Posts

    • No1UKnow
      Transmission Woes :-(

      By No1UKnow · Posted

      Well, I received a message from the dealer...
    • Atomicgrl
      ‘25 Silverado purchase- back to dealership for bumper/radio issue

      By Atomicgrl · Posted

      The no sound problem is the audio amplifier. The audio amp has a heatsoak issue in some circuitry which causes it to miss the wakeup handhake. If it doesn't respond within a certain time parameter, then you get no sound. I brought it in and had the software update, but after further testing the tech made the call for a new audio amplifer. The software update I belive gives more time for the amp to respond, but if the amp is defective then you can still get no audio at times. After the update it went 12 days before no sound. After doing some research, apparently the fix is a new (updated) audio amplifer, the circuitry internally has been improved to better deal with heat. I had to wait 2 1/2 weeks because at the time, it was on backorder with no eta. Well the amp came in earlier this week. I had the amp and programming work done today. After picking it up I stopped at a few places, and whenever I started my truck, the audio was on instantly, so whatever they did it appears to work because it's never had sound that quickly......Hope this helps
    • Jus Cruisin
      Rear Crew Cab Door Wont Open

      By Jus Cruisin · Posted

      Make sure the latch mechanism is properly greased. Look at the catch for fresh marks/scratches. And see if it has moved a little, too. 
    • PBNB
      Thoughts on these wheels?

      By PBNB · Posted

      I have the 18" black mutilspoke wheels that came with my truck. I like them as they are very subdued and look good with the 295/70's    I am sure that the next set of wheels I get will be some after market all black wheels. Or maybe some AT4X wheels.
    • Grumpy Bear
      OCI, not when but why?

      By Grumpy Bear · Posted

      Interesting question which you partly answered in the word 'potentially'. I think that is going to be a 'point of reference' inquiry. What are the touchstones?    This will sound petty but it is the main source of end fighting in threads on this topic. Define a motors "Life". Think about the various arguments that have been entertained on these pages in that very argument.    I can only speak from my viewpoint. Engine "Life" in my world is defined by power cylinder integrity. For the majority of engines it is the bore/ring interface that quits first. Loss of seal. Oil consumption and loss of power. Most Pro motor builders would agree and there is a good deal of information on using "Leak Down" as a primary indicator of bore integrity. At home a compression test is more the thing. If we can agree on that then I think CC Jensen has done its homework and I'd find it valid.    Now by my own definition, Dizzy, wife's Ecotec 2.4 I-4 has been dead since about 80K miles. And yet we have logged over 200K miles more on it. "Life" and "Usefulness" are therefore independent.      I know a mature fella right now who has just hit 300K on a Mitsubishi 3A92 NA MPFI motor and has done compression test every 100K. It was 205 psi after break in and is now about 195 and still even. He uses shelf oil but good filters and adheres to a 3K mile OCI. He even do UOA's on each of them for the first 50K.      I also know a fleet mechanic with that same motor that gets 300 to 500 K out of them but the are oil using, wristpin sloppy, skirt slapping motors. He ran one with a piston pin so loose the piston was bouncing off the cylinder head for about 20K miles before he called TOD. Both of them claim success.         

  • GM-Trucks.com Clubs

  • Popular Contributors

×
×
  • Create New...