We have a 2008 GMC Envoy here that after u drive it for a while it will start to smoke and miss. The miss is cyl 5,7 every time.
Have had the valve cover off and it all looked good. Did find one vac leak and fixed it but did not fix it. U do have to drive this thing for about 15 min for it to start doing it. If u keep driving it it will go away. Had to clean the srean under the oil psi switch when we frist got it. This is our truck. Been looking off and on now for a few months now.
2008 GMC Envoy Denali 5.3L - Miss & Smoke
- fortknoxx
- 1500 Club Master Plus Contributor
- Posts: 1873
- Joined: Wed Sep 13, 2006 6:09 am
- Location: High Point, NC
- Contact:
Re: 2008 GMC Envoy Denali 5.3L - Miss & Smoke
the coil might be over heating and sending wrong/intermittent/no fires to the plugs. Allowing fuel to collect unburned in the not firing cylinder. Then BAM!
T-N-T (Tina Nuse-Tolar)
Gone but not forgotten...Camper Bob's
609-760-7079 Cell
Gone but not forgotten...Camper Bob's
609-760-7079 Cell
- steven kiser
- 5K Holy Smokes Contributor
- Posts: 6184
- Joined: Fri Jul 06, 2007 4:58 am
- Location: eastern ma.
Re: 2008 GMC Envoy Denali 5.3L - Miss & Smoke
watch O2 signal. If it tanks it will kill cylinders
never argue with a fool, they'll drag you down to their level and beat you with experience