Monorail_Red

So I've only had the truck for about a year and a half, currently about 29k miles. Got my first CEL on Sunday, and it cleared itself on Monday. Had an oil change scheduled today anyway, had the dealer check it out while I was there. Turned out to be P0300, which I understand is some sort of a misfire code. Did some research and I didn't see this turn up much for the later model years. Dealer said all looks okay, basically said must have been a fluke either due to the temps changing back and fourth recently, or even maybe a flooded cylinder. My dealer has always done good for me - not that I want to doubt them but should any of this concern me?

I mean it has been cold, but nothing below zero the past several weeks...I wouldn't think the engine should be THAT sensitive to the cold compared to other locations where it is can be much much colder. Last winter we had som extreme temps we didn't see yet this year, and I didn't have a problem. And I always let it warm up before driving in the winter...not like I just startup and go.

For the 24hrs the CEL was on, there was no rough idle/performance and the truck was its normal self. Literally the only abnormality was the CEL being lit. Anybody seen or experienced this before?

Monorail_Red

Just an update...all has been well until this morning. Got the CEL again after driving to store while idling in parking lot for about 10min waiting for it to open. Similar to before - only thing abnormal is the CEL being lit. I'm contemplating picking up my own scanner to see if I can get more information on the CEL.

Pugly

intermittents are very difficult to find and diagnose - especially intermittent misfires

Monorail_Red

So it continues...I now have a "SERVICE TRACTION CONTROL" message, and I have the indicators lit saying that Stabilitrak and Traction Control are disabled. Another thing I found interesting...normally I keep the DIC at the instant MPG screen which also shows the V4/V8 modes. I was idling so of course it said 0 but the 0 kept flickering back and forth between 0 and --. For a moment even the gauges were doing something a bit strange - trembling is the best way I can describe the behavior.

Stepping back a bit - I forgot when it was exactly but back in September or October I had an issue where I would start the truck, and it would stall out saying "SERVICE ANTI THEFT SYSTEM". Both the keys and the key reader were good but there was some sort of anti-theft module they replaced and since then it hasn't been a problem. I almost wonder if that was actually a precursor to what I'm experiencing now?

Anyway - it's going back to the dealer tomorrow as there is obviously another underlying issue.

Monorail_Red

Got a call back from the dealer. This time it was (if I recall correctly) code P0301 or whatever the corresponding code is for cylinder 1 misfire. Like what Pugly said I understand a random misfire can be hard to pinpoint, so I'm happy this time the CEL code corresponded to a specific cylinder. They ran a compression test among other things and determined the spark plug was bad. I will be picking it up after work and see how things go.

Chevrolet Customer Service

Hey There,

We're sorry to hear that you experienced this problem with your vehicle. Please feel free to follow up with us regarding your dealership visit. We will be happy to document your feedback. If we can be of any other assistance, we can be reached via private message. We look forward to hear from you soon!

Kristen A.
Chevrolet Customer Care

Pugly

and what does that do???

Monorail_Red

Just for the sake of updating this thread (hopefully) one last time...looks like it was indeed the spark plug as I have not had the CEL since my last visit. The first time I had this checked out (and no actions were taken other than clearing code) it was back on within 48hrs. Think we're good to go.

Monorail_Red

Got another CEL last night and a slight tremble at idle - possibly another bad plug? I'm bringing it to a different dealer this time, because last year when this happened it took 2 trips to get the spark plug replaced. First visit they blamed it on the change in temperature, which I thought was BS. Currently 46k miles on the truck.

Monorail_Red

Regarding my post from the 25th, the CEL seemed to work itself out. But I got another CEL this past Tuesday. I brought it in to the dealer today, and its all set (for now). I had another bad spark plug in cylinder #1.

I was disappointed to find out this was not covered under warrantee. I assume GM considers the engine part of the power train, and I'm nowhere near the end of my 5 year 100,000 mile power train warrantee. Furthermore, the ACDelco plugs themselves have a 100,000 mile parts and labor warrantee.

I'm having trouble understanding 1) why this was not covered under warrantee and 2) why this is the 2nd spark plug, which is supposed to be a 100k mile plug, to go bad in the same cylinder within 18,000 miles.