Lean Burn Misfire??????

[plainvanilla]

Just bought my 05 Silverado, 3800 miles, dealer demo, 7 weeks ago and have only driven it about 5 weeks, since I was out of the state for 2 weeks and took the Suburban.

 

In park, at idle, warm engine, it has a slight to moderate intermittent miss.

It will jerk and shake for a spilt second and run fine. It might go unnoticed by a peson with no automotive background, but I think it needed looked at.

 

 

When the AC is on and the computer bumps up the idle a bit, it is alot less noticable, or when in drive at a light while stopped at a light, it is less noticable.

 

 

The dealer took it in, ran some injector cleaner though the intake(waste of time and money) and called it a lean burn misfire. They said that the computer had no codes for misfire and I agree, no lights were set or even have flashed. They said that in order for GM to get the truck to pass emissions at idle they had to lean it out to the point of causing a slight lean misfire occasionally. I say BS!

 

What should I do next, besides continue to monitor and see if it clears up as I continue the break-in?

 

Thanks for taking time to read this,

 

 

Mark

[GM-Tech]

Hard to say whether or not you have a problem, and I'm going to say something you probably won't like.

 

Some customers are very picky and expect not to be able to feel the engine running. I've had customers tell me "it misses horribly!" and when I sit in the truck with them they say, "See, see!" My goodness, you can feel that the engine is running, nothing more. It's a truck and an internal combustion engine for pete's sake, not an electric motor. Yeah, there's an occasional little bump that you might feel. That's the way it is.

 

If it would go unnoticed by someone without an automotive background, it's probably unnoticeable. Go sit in a half-dozen similarly equipped trucks and see if they are similar. Don't expect every one to be identical, but out of a half-dozen, you should get a good comparison.

[plainvanilla]

Hard to say whether or not you have a problem, and I'm going to say something you probably won't like.

 

Some customers are very picky and expect not to be able to feel the engine running.  I've had customers tell me "it misses horribly!" and when I sit in the truck with them they say, "See, see!"  My goodness, you can feel that the engine is running, nothing more.  It's a truck and an internal combustion engine for pete's sake, not an electric motor.  Yeah, there's an occasional little bump that you might feel.  That's the way it is.

 

If it would go unnoticed by someone without an automotive background, it's probably unnoticeable.  Go sit in a half-dozen similarly equipped trucks and see if they are similar.  Don't expect every one to be identical, but out of a half-dozen, you should get a good comparison.

 

<{POST_SNAPBACK}>

 

 

 

I sure don't mind the feel of the engine running.

I can feel my 97 Suburban and my 1990 Cherokee, but this thing has a "shake" and "jerk" when it misses. The fact that they told me this term "lean burn misfire" is evidence enough that others have brought their vehicles in also and they made up a name for it or got it from a training manual.

 

With a distributor-less ignition and eight coil packs I just don't think one can be weak without causing a constant issue.

 

I'll keep driving it and check back with them on 3500 mile intervals, maybe it will miss enough to set a code. I would also hope if others have reported this, there may be a TSB in the future.