'07 rumble always at 24/25mph when slowing down

[S1W99]

'07 rumble always at 24/25mph when slowing down.

Brakes replaced, but not sure what it could be. I read something about them AFM but reality have no idea.

Thanks

 

[BG1988]

'07 rumble always at 24/25mph when slowing down.

Brakes replaced, but not sure what it could be. I read something about them AFM but reality have no idea.

Thanks

check the tires for rocks this can make the tire go out of balance

 

[wjburken]

'07 rumble always at 24/25mph when slowing down.

Brakes replaced, but not sure what it could be. I read something about them AFM but reality have no idea.

Thanks

Set your DIC to show which mode your vehicle is in, V8 or V4 and see if the shudder coincides with when it switches. Chances are pretty good that your shudder is occurring when the motor is switching modes.

 

[iamdub]

'07 rumble always at 24/25mph when slowing down.

Brakes replaced, but not sure what it could be. I read something about them AFM but reality have no idea.

Thanks

I'm with Wade on this one:

Set your DIC to show which mode your vehicle is in, V8 or V4 and see if the shudder coincides with when it switches. Chances are pretty good that your shudder is occurring when the motor is switching modes.

 

[Geotrash]

'07 rumble always at 24/25mph when slowing down.

Brakes replaced, but not sure what it could be. I read something about them AFM but reality have no idea.

Thanks

You didn't say which model/engine you have. If you have the 6.2 then you don't have AFM, so I might look for a driveline cause. Can you provide more info, please?

 

[S1W99]

You didn't say which model/engine you have. If you have the 6.2 then you don't have AFM, so I might look for a driveline cause. Can you provide more info, please?

I have AFM, 8 to 4 cylinder when slowing down. Ricochet is flex fuel 5.3 I believe.

 

[S1W99]

Yes, that's it. I ordered the range plug in hopes it addresses it.

 

[iamdub]

Yes, that's it. I ordered the range plug in hopes it addresses it.

It should. You kinda jumped the gun on it, but there are some drawbacks to the Range that you might should be aware of:

1) If your area requires inspections and they need to plug into the OBDII port, you'll have to remove the Range and complete a number of drive cycles to satisfy readiness monitors before your vehicle will be ready for testing. The drive cycles could take a few days or a few weeks to complete. It may not cause any problems, but having a system that's already ailing sit dormant for a year then suddenly recommissioned (when you remove the Range for inspections/testing) just doesn't sit well with me.

2) Unless it has been resolved in soft- or firmware updates, the Range will need to be removed if the vehicle will be parked for extended periods (a week or so) to avoid draining the vehicle's battery.

3) If you can afford to have your vehicle down for a few days, you can send the PCM to a guy in Missouri to have the AFM turned off in the tune. This costs $50 plus shipping to him (return shipping is included in the $50). It wouldn't require anything to be plugged into the port and AFM would be permanently disabled. Emissions/inspections will not be affected. If you ever need to mechanically delete the AFM components (failing or failed lifter(s), etc.), then you wouldn't need any special tuning afterward to start and drive it since it has already been shut off in the tune. https://lt1swap.com/afm_delete.htm

 

[wsteele]

It should. You kinda jumped the gun on it, but there are some drawbacks to the Range that you might should be aware of:

1) If your area requires inspections and they need to plug into the OBDII port, you'll have to remove the Range and complete a number of drive cycles to satisfy readiness monitors before your vehicle will be ready for testing. The drive cycles could take a few days or a few weeks to complete. It may not cause any problems, but having a system that's already ailing sit dormant for a year then suddenly recommissioned (when you remove the Range for inspections/testing) just doesn't sit well with me.

2) Unless it has been resolved in soft- or firmware updates, the Range will need to be removed if the vehicle will be parked for extended periods (a week or so) to avoid draining the vehicle's battery.

3) If you can afford to have your vehicle down for a few days, you can send the PCM to a guy in Missouri to have the AFM turned off in the tune. This costs $50 plus shipping to him (return shipping is included in the $50). It wouldn't require anything to be plugged into the port and AFM would be permanently disabled. Emissions/inspections will not be affected. If you ever need to mechanically delete the AFM components (failing or failed lifter(s), etc.), then you wouldn't need any special tuning afterward to start and drive it since it has already been shut off in the tune. https://lt1swap.com/afm_delete.htm

Good advice.

Although my ‘07 shifts from V8 to V4 mode seamlessly, I decided to install the Range device as I don’t like the number of AFM lifter failures I see posted on many boards, YouTube, etc.

The device works flawlessly to disable V4 mode. When I learned that by pulling the range device out, multiple readiness monitors were reset, hence you had to drive around for a number of trip cycles with it out to reset those monitors before my truck would be ready for emissions testing (bi-annual here), at first I didn’t think anything about it.

The more I thought about it and learned how the AFM system works and how it generally fails (reading on these very forums), I started to have second thoughts about the wisdom of using the Range device in a situation where periodic emissions tests were a way of life. Before I sell my Range device, I decided to see how much driving I really needed to do to reset the monitors on my Yukon. I am at 200 miles and 5 trip cycles (cold start, one complete GM trip cycle each) and the monitors are still not ready.

I decided to buy a Diablo Predator (about $370 shipped new to me) and turn off the AFM in the software of my PCM, instead of using the range device.

I just got the Diablo device yesterday and reading the manual last night, it will be very easy to disable the AFM using it.

There is one gotcha that I should mention with regard to the Diablo Predator that I read about in the manual. They recommend restoring your system to stock before taking your car to a dealership for service. The reason for this is the way the unit assures you aren’t using it for a bunch of different vehicles is it stores your stock tune in its memory, before it changes your PCM’s software. The device only then will work with your engine, in that exact configuration. If the dealer changes your PCM software for some reason, when you go to restore your chosen setup from your Diablo Predator after the service, it won’t recognize your dealer updated software and your Predator will no longer be able to change things on your vehicle. Diablo may be able to restore your Predator so it can change your “tune”, but if not, your Predator is essentially bricked.

I am still mulling how I feel about this glitch in my plan, as I really don’t want to be turning AFM on and off, whether it be for emissions or dealer service work. Hundreds of heat cycles between turning the AFM on for a brief period and then back off again, seems to be like a bad idea.

I may go ahead and disable the AFM with the Predator and go back to doing all my own work on my car again, not the end of the world. It is just that my local dealer happens to be so cost effective and really good, I kind of liked not busting my knuckles on the old gal.

Sorry for the long tome, hard to cover all these details succinctly, if writing isn’t your best skill.

 

[iamdub]

Good advice.

Although my ‘07 shifts from V8 to V4 mode seamlessly, I decided to install the Range device as I don’t like the number of AFM lifter failures I see posted on many boards, YouTube, etc.

The device works flawlessly to disable V4 mode. When I learned that by pulling the range device out, multiple readiness monitors were reset, hence you had to drive around for a number of trip cycles with it out to reset those monitors before my truck would be ready for emissions testing (bi-annual here), at first I didn’t think anything about it.

The more I thought about it and learned how the AFM system works and how it generally fails (reading on these very forums), I started to have second thoughts about the wisdom of using the Range device in a situation where periodic emissions tests were a way of life. Before I sell my Range device, I decided to see how much driving I really needed to do to reset the monitors on my Yukon. I am at 200 miles and 5 trip cycles (cold start, one complete GM trip cycle each) and the monitors are still not ready.

I decided to buy a Diablo Predator (about $370 shipped new to me) and turn off the AFM in the software of my PCM, instead of using the range device.

I just got the Diablo device yesterday and reading the manual last night, it will be very easy to disable the AFM using it.

There is one gotcha that I should mention with regard to the Diablo Predator that I read about in the manual. They recommend restoring your system to stock before taking your car to a dealership for service. The reason for this is the way the unit assures you aren’t using it for a bunch of different vehicles is it stores your stock tune in its memory, before it changes your PCM’s software. The device only then will work with your engine, in that exact configuration. If the dealer changes your PCM software for some reason, when you go to restore your chosen setup from your Diablo Predator after the service, it won’t recognize your dealer updated software and your Predator will no longer be able to change things on your vehicle. Diablo may be able to restore your Predator so it can change your “tune”, but if not, your Predator is essentially bricked.

I am still mulling how I feel about this glitch in my plan, as I really don’t want to be turning AFM on and off, whether it be for emissions or dealer service work. Hundreds of heat cycles between turning the AFM on for a brief period and then back off again, seems to be like a bad idea.

I may go ahead and disable the AFM with the Predator and go back to doing all my own work on my car again, not the end of the world. It is just that my local dealer happens to be so cost effective and really good, I kind of liked not busting my knuckles on the old gal.

Sorry for the long tome, hard to cover all these details succinctly, if writing isn’t your best skill.

Yes, your thread is actually the freshest one on my mind and what I was thinking of when I wrote my reply. I wouldn't consider the dealer reflashing your PCM and killing the Diablo a "glitch". It's so one person can't buy a Diablo and use it on all of their friend's vehicles or sell it on FB or craigslist so 1,000 other people can tune their rides. It takes your stock PCM's info and stores it ("marrying" it to your vehicle) then uploads its custom tune. If the dealer sees this and reflashes it, even if just to rule out what they think may be a potential cause for whatever they're diagnosing, the Diablo won't recognize the PCM as it's "spouse" when you plug it back in to reflash your PCM. Since it's so simple to do, you can reflash the stock tune in the dealer parking lot. Them driving it from there and into the bay shouldn't present a situation for AFM to engage (slow speed, not up to temp, etc.). Of course, this would be dependent upon what it's at the dealership for as they may have to road test it. If you have a good relationship with them, have them type in all caps, highlight and circle on the service order instructions to NOT reflash the PCM under any circumstances without consulting with you first. To perform their full diagnostics on a particular system per their protocol, they may have to have a stock tune. Otherwise, they may refuse to work on it. The first scenario that comes to mind would be diagnosing a misfire. I'm sure you'd try to perform your due diligence to diagnose this on your own, perhaps using the help of this fine forum, before bringing it to a dealer. For them to track down an inexplicable misfire, they'd LOVE to point the blame at a faulty aftermarket tune right off the bat.