25,000 Miles And Afm Started Causing Vibration

[richwin]

I have an 07 GMC crew cab with 5.3 and over 25,000 miles and last Monday I noticed a horrible vibration and I have it narrowed down to when the AFM goes into 4 cyl mode. My question is will the dealer do anything to fix this? Is there a fix out there to do away with it? Thanks for your time.

 

Marc

[brims]

No, there's a TSB saying this is normal.

[cerbomark]

Having mine turned off next week

[richwin]

Having mine turned off next week

 

 

What is the cheapest way to get it turned off? Will the dealer do it?

 

Thanks for all your help

 

Marc

[brims]

Having mine turned off next week

 

 

What is the cheapest way to get it turned off? Will the dealer do it?

 

Thanks for all your help

 

Marc

 

 

You need to get a tune, or get a hand held tuner. No the dealer won't do it. You'll want to read about the warranty stuff and make sure you know what needs to be done just in case you need to go for warranty work.

[rogerf]

I have an 07 GMC crew cab with 5.3 and over 25,000 miles and last Monday I noticed a horrible vibration and I have it narrowed down to when the AFM goes into 4 cyl mode. My question is will the dealer do anything to fix this? Is there a fix out there to do away with it? Thanks for your time.

 

Marc

You want to start with the dealer to find the source of the vibration while the truck is under warranty. This is obviously abnormal performance for your truck based on your original post. Would not tune or modify anything until the dealer rules out the possibility of mechanical problems causing this vibration.

[a_guerrajr]

There is an issue with the lifters.

Not sure if that could be your issue.

Dealer first

[2005LT]

+1

Sounds like a dealer visit is in order.

[brims]

I guess it can't hurt to ask the dealer, but it sure sounds like it's doing what many others feel that is "normal"

[2005LT]

Possibly, but he mentioned that it got bad on Monday so I assume something changed.

[richwin]

Possibly, but he mentioned that it got bad on Monday so I assume something changed.

 

 

Latest update from the dealer. They are saying that the motor mounts and tranny mount needs to be replaced. They compared my truck to another one and they said with mine they could feel the same vibration as the engine in the fender. I have my doubts, even though it sounds like a good theory, but we will see. They are supposed to have the parts to fix it on Friday. Keeping my fingers crossed.

[pm26]

Possibly, but he mentioned that it got bad on Monday so I assume something changed.

 

 

Latest update from the dealer. They are saying that the motor mounts and tranny mount needs to be replaced. They compared my truck to another one and they said with mine they could feel the same vibration as the engine in the fender. I have my doubts, even though it sounds like a good theory, but we will see. They are supposed to have the parts to fix it on Friday. Keeping my fingers crossed.

 

 

What a coincidence. I am having the clutch replaced on my '99 Mazda 626 V6 with 230K miles on it, and they just told me that my front motor mount is completely broken. Cannot complain after ten years and almost quarter of a million miles though. A bit too early on your truck, wouldn't you say?

[C. Charles Hahn]

If those mounts truly are gone already on your truck, I have to ask, either 1) are you REALLY hard on your truck? or 2) are the factory motor mounts THAT shitty?

 

Wow.

[GPGuy]

I'd go to the dealer first for sure! Definitely sounds like something changed. I've read a lot about other members having this issue but I can't say as I've had had a problem with mine.