P-308 code need help!!!

[mfd#1]

Hey I need help I have an 2002 Tahoe and it's throwing a P-308 code which I know is cycliner 8 mis-fire... I have changed plugs and then coil pack on cycliner 8 and it still is running ruff when in slow traffic are stopped at stop sign are red light ... The wost thing right now is that it's drinking fuel as fast as I can put it in ... I need some help.. The people at dealers are telling me it's going to take about 2,500.00 to fix it... The light is one when at a idle and when I give it gas it goes off strange to me... But 2500.00 is really bad at this time of the year are anytime really.. Can someone please help me out with this...

[konigandy6]

Hey I need help I have an 2002 Tahoe and it's throwing a P-308 code which I know is cycliner 8 mis-fire... I have changed plugs and then coil pack on cycliner 8 and it still is running ruff when in slow traffic are stopped at stop sign are red light ... The wost thing right now is that it's drinking fuel as fast as I can put it in ... I need some help.. The people at dealers are telling me it's going to take about 2,500.00 to fix it... The light is one when at a idle and when I give it gas it goes off strange to me... But 2500.00 is really bad at this time of the year are anytime really.. Can someone please help me out with this...

The dealer is telling you $2500 to fix the issue? Did they diagnose the problem or are they guessing? Did you get a compression test done?

Possibilities:
1. worn camshaft lobe and/or lifter roller
2. a sticking valve
3. valve leakage
4. a broken valve spring
5. injector

[thearborbarber]

How is your coolant level? I ask because gm had some crappy heads made castec that were known to crack.

It's a stretch but if it cracked near the #8 cylinder....