6.2 missing, traction control, stability lights

[FBYamaha]

Fuel pressure is solid. 50 psi with key on and 60 running. I'm not sure if it helps but I'm getting The CAT/EVA/O2S/HTR red readings on the Innova. The ground to the block also looks good and solid but tomorrow I'll take off and clean all the connections I can find. Thanks for the help! As cheap as it is, I might drop in a crank position sensor while I'm under there.

 

[Doubeleive]

Fuel pressure is solid. 50 psi with key on and 60 running. I'm not sure if it helps but I'm getting The CAT/EVA/O2S/HTR red readings on the Innova. The ground to the block also looks good and solid but tomorrow I'll take off and clean all the connections I can find. Thanks for the help! As cheap as it is, I might drop in a crank position sensor while I'm under there.

If you had the battery disconnected recently the sensors will show "not ready" till you drive it a little bit and they self test.
clean the maf while you at it, I typically see them start taking a dump at the mileage you are at cleaning it wont "fix" it but if it is dirty it could be part of the problem also that stupid maf can throw the whole thing out of whack.

 

[FBYamaha]

New crank position sensor, cleaned contacts, cleaned MAF nothing resolved. Funny thing when I connected the OBD it pulled up the misfire on Cyl No.1. I switched 1 & 3 to see if it would pull that up, just got the random code. Here I am chasing parts....just like I didn't want to but here we are.

 

[Doubeleive]

New crank position sensor, cleaned contacts, cleaned MAF nothing resolved. Funny thing when I connected the OBD it pulled up the misfire on Cyl No.1. I switched 1 & 3 to see if it would pull that up, just got the random code. Here I am chasing parts....just like I didn't want to but here we are.

what did you switch on 1 & 3 ?

 

[FBYamaha]

what did you switch on 1 & 3 ?

I just swapped the coils to see if I’d get a code on #3 which I thought would indicate a bad coil. It didn’t change. Still getting a #1 misfire.

 

[Doubeleive]

I just swapped the coils to see if I’d get a code on #3 which I thought would indicate a bad coil. It didn’t change. Still getting a #1 misfire.

I would pull the plug then and check it out, maybe swap plug and see and then the wire also, process of elimination

 

[FBYamaha]

All the plugs and wires are new since this began. I would think that has already been eliminated as a possibility. The next logical step I can think of would be compression check. Since I don't have one of those, next stop...repair shop and see what they can find.

 

[swathdiver]

I've done a bunch of searches and hate to ask in case I'm missing something. 2007 Denali, 6.2, 170,000 miles. Just bought it (back from the ex-wife) It was running great, ran some seafoam through it since I'm pretty sure she did nothing to it since the divorce. Changed the oil. Probably put 1000 miles on it. Fired right up the other day, pulled out of the driveway and is started missing.....badly. Engine light, traction control light, stability control light. I let is sit for a couple days and just fired it up. Starts right up, maybe with a little miss then it goes downhill from there and all symptoms return. When it first happened I changed the plugs and wires. Plugs all looked good. We did have a similar problem three years ago and they replaced a broken valve spring. I can't imagine it would be that again. Any other ideas before I limp it to the repair facility?

At that mileage on a 6.2 my first thought was a valve spring. Pull the covers and have a look if you don't have a Tech-2 to watch for misfires.

 

[swat2380]

All the plugs and wires are new since this began. I would think that has already been eliminated as a possibility. The next logical step I can think of would be compression check. Since I don't have one of those, next stop...repair shop and see what they can find.

New plug wires can be bad. You just said new plugs and wires since this began so did it start after you swapped them?

 

[FBYamaha]

Word from the mechanic "yeah, bad news, you need a new engine"
No compression in No.1 which is was pretty sure was the case. I explained I've had this before and asked him to pull the cover and look at the springs. I wish I would have insisted on replacing all of them when No.7 went. He should be able to confirm tomorrow.