GM truck help.

[S Sidwell]

Have you checked the intake for leaking yet?

Steve, Samsung On5 using Tapatalk

 

[Bigmac]

It has always pinged , since I got it at 100k I have never had a code come up, just stumbled at idle when cold and gas mileage gone now. The factory exhaust was damaged by former owner and I replaced with oem. It is puzzling to me that I never see any codes.

I misread your first post, I thought it threw a code! Most 6.0 I have seen get 16 hwy, have you checked the plugs to see if any are dirty? That might help to see any issues. Could have a dirty or leaky injector? Did you buy or change tire size? I would pull the plugs and see if any look dirty

 

[KYsawman]

Have you checked the intake for leaking yet?

Steve, Samsung On5 using Tapatalk

No unfortunately I am on my 7-12’s of night shift and have not got to check yet.

 

[KYsawman]

I misread your first post, I thought it threw a code! Most 6.0 I have seen get 16 hwy, have you checked the plugs to see if any are dirty? That might help to see any issues. Could have a dirty or leaky injector? Did you buy or change tire size? I would pull the plugs and see if any look dirty

I put new plugs and wires on it at 100k two years ago when I first bought it. I wonder if the injectors are going bad. The truck has 156k now.

 

[KYsawman]

I put new plugs and wires on it at 100k two years ago when I first bought it. I wonder if the injectors are going bad. The truck has 156k now.

Has always had 265-75-17 on it, I think stock was 245-75-17, but had new tires when I got it.

 

[Dustin4185]

I've never ER got better than 15 MPG in mine. It's an 04. The intake gaskets aren't bad, I did splurge for a topside creeper to do it though. My fat belly gets in the way laying on the grill!

 

[Bigmac]

I put new plugs and wires on it at 100k two years ago when I first bought it. I wonder if the injectors are going bad. The truck has 156k now.

I would pull the plugs to see if one cylinder is the culprit, or if it is clean or even then it could be a sensor or major system

 

[ucm931]

Yeah, 20mpg seems absurdly good mileage for that thing. Did you hand calculate or just go by what the 'puter displays? They are typically off the mark. Do a hand calc based on fuel used and mies driven when you fuel up. Come to think of it tho, hand calc wouldn't be accurate either because of the tire size difference.......unless the tire size was updated with a programmer.

Also wouldn't be the first time I heard of a used vehicle missing the check engine light bulb. Have Autozone scan it for ya and see if any codes pop.