2011 Silverado 1500 P0300 Code

[TheTrueMoron]

Tonight my truck's check engine light came on suddenly. Then as I was getting close to my destination the truck started shaking a little (felt like the engine) and then the "Service Stabilitrak" and "Service Traction Control" messages came on. I'm not sure why these are affected if it's an engine issue but the brakes did shudder while I was braking at slow speeds. When I accelerate the check engine light blinks. The truck now has a definite engine shake occasionally and it is always shaking when in reverse now. I checked the codes and the only one was the P0300 code (multiple/random cylinder misfire). I'm thinking about just having it towed to the dealership Monday morning (hoping it will be covered under warranty) and letting them figure it out and fix it but money is short this time if year...

 

Is this a somewhat common code with a common fix? Or are there some simple diagnostic things I could do myself with minimal tools to try and figure out the problem and fix it?

 

Thanks!

 

The truck: 2011 Silverado 1500 Z71 4x4 5.3L (Purchased new July 2011)

[Jsdirt]

Wow ... on a 4 year old truck! SMH ....

 

That code is a royal pain in the ass to diagnose. Could be any number of things, from leaking intake gaskets, to a loose or broken wire, to a blown head gasket.

 

If you bought it new, and are under 36k miles, your still covered under the bumper-to-bumper warranty. Let them deal with it.

[TheTrueMoron]

Well the Service Adviser called me back the other day and it's not something simple. The mechanics took a look and found a damaged spark plug with a lot of fouling and some other things that they couldn't fix so they are sending it to their "Heavy Repair" department. I'm still waiting to hear back from them but they did say that it's not simple and that the problem is somewhere major in the engine. I was told that unless it was some outside factor that caused the issue that it would be covered under warranty given what they know so far. I asked if there would be any extension on the warranty after this but I was told that the 5 year/100,000 mile warranty still applies which would leave me out of warranty come July. Is this true?

 

So, given that the engine will be in need of major repair, what can I expect in the future? Am I going to have more issues down the line as a result? I've always heard that once you do internal work on an engine that it tends to have more serious and frequent problems after. I was really hoping to keep this truck for 20 years if I don't get hit too seriously and too often on the road but now that may seem out of reach. Any answers are appreciated! Thanks all!

[Jsdirt]

Not true ** IF ** the engine repairs are done RIGHT. Under warranty, I'd be keeping a close eye on what they do here. They love to cut corners when warranty work is involved. My buddy grenaded his V6 Camaro after GM cut corners and attempted to just bearing-slap a damaged engine (due to excessive oil consumption that they were monitoring ... apparently not closely enough ... ).

 

In that case, the correct option would be to just install a new long block. They tried to cut corners to save a buck, and it bit them squarely in the ass. They tried and tried to blame my buddy, and to weasel their way out of it, but he was having NONE of it.

 

Some dealers are better than others. YMMV ...

 

STAY ON THEM - make SURE they do it right.

[TheTrueMoron]

Just got it back today. The issue was in the #1 cylinder and after some personal research it looks like this was caused by the AFM, and this is not the first time someone has had this problem with this engine. They put in an oil deflector to keep oil from spraying towards the inactive cylinders when the AFM is active, and the put in a new rocker arm cover and they performed "decarbonization" per Service Bulletin 10-06-01-008. And they replaced the bad spark plug (which I attached).

 

Now I have a few more questions:

1. Should I get all the spark plugs replaced now, or is it okay to just replace one at a time?

2. How often are the spark plugs supposed to be changed on these trucks?

 

Thanks again!

 

[Jsdirt]

Jesus Christmas ... that's deja-vu right there of my #2 cylinder on the original 4.3 V6 that came with my '89 S10 Blazer. That engine burned a quart of 20w-50 in single-digit Fahrenheit temps ... but it was over 2 decades old with who knows how many actual miles - judging from the wear inside when I yanked the heads, and interior wear, somewhere north of 300k miles.

 

They say these plugs are good to 100k. I didn't buy that, and changed mine at 65k, thinking they would weld themselves into the head well before 100k. The plugs weren't worn at all. Also, I was pleasantly surprised to find that GM actually used anti-seize compound on ALL the plugs. Miracles never cease ... but this was in '07 - we've seen some pretty drastic cheapouts the past several years at GM, so that may be another item cut from the list to save money ... bottom line is, it's cheap insurance to change them sooner, rather than later, and put the anti-seize compound on yourself.

 

I'm thinking I;d better start finding some $$$ and getting this damn AFM tuned out, before I have to yank my engine before I even hit 100k miles ...