Tom Martin

I am helping a friend who has a LS 6.0, which my scanner tells me it came out of a 2004 GMC Denali. It's in a 50 ford pickup and it's running rough as a cob, however, it ran great 6 months ago. I put a timing light on each plug wire to see if they were firing. I am getting fire on cylinders 8,3, and 5. I also pulled the wire from the coils on all cylinders one at a time. These same three cylinders bogged the engine down when I pulled the plugs from the top of the coils, and none of the rest did.not. Have I had 5 coils go bad? The truck has been sitting for probably six months, and it's in a garage, but it has a rock floor and there is a LOT of moisture in the garage. Could that be a factor? Any suggestions? All help is greatly appreciated.

G Atsma

Check for corroded connections EVERYWHERE, including ALL grounds.

00pooterSS

iTrader: (40)

If it stays in storage a bit check all the wiring real close for damage from rats.

After that I'd look at the crank sensor.

No fire randomly on 5 coils isn't very likely to be caused by the coils just all the sudden failing.

jetech

Wow! I'm suprised it will run on 3 cylinders. I agree with 00pooterSS check the wiring for critter damage. Hurry before they chew through the remaining wires