I disconnected my battery for a few hours a month ago. now I've lost the
performance and super firm shift that I used to have when I bought the truck. I'm guessing the truck had been either "programmed" or had an aftermarket chip installed.. but if it had a chip, should not lose the programming.

The truck has not "relearned" the shift or performance so I rule out the short term memory thing that gets relearned shortly after 30 miles.

I think all I can do is
1. verify that there is no aftermarket chip
2. no choice but to purchase a programmer / tuner and reprogram.

any suggestions would be greatly appreciated

Thx

 

If it makes you feel better, nope, there is no way that disconnecting the battery removed any previous performance tuning - it doesn't work like that. It's a ROM chip that stores that info, not RAM, so it's not stored in "volatile" memory that would be wiped out by a battery disconnect. All that disconnecting the battery will do is clear out previous adaptive strategy adjustments.

 

You’re going to need more than 30 miles for the PCM to re-learn the adaptive strategy. Give it some more drive-cycles and I think you’ll be OK again

 

On several occasions I have saw it take as long as 30 days to return to the previous operation after the PCM was powered down.
On one occasion recently I had the PCM reflashed with the same program and no updates and was supprised the truck ran very well without waiting any amount of time.

 

Thanks for the input.
Its been probably 650 miles since this started. I've since cleaned the maf, air filter and changed oil to no avail.

The shifts are just flat and boring. Shifts used to somewhat launch the truck into the next gear. Could old tranny fluid cause flat shifts or reduce shift pressure? Its time for tranny fluid and filt change anyway so thats on my list for the weekend.

Also considering pulling the battery cable again, then hot rodding it hopeing it will get a clue and stiffen up.. lol.

Thanks again

 

Here is basicly how the trans is shifted.
The PCM decides when the shift will occurr and the firmness is how the PCM operates the Trans pressure control valve.
In programming, the circuit pressure is raised to firm up all the shifts since all circuits use the same pressure source.
Using mechanical means in the trans valve body is the better way of the two ways. While the mods do raise the pressure, it's more of an individual operation at each point and does not raise the 'overall pressure' to a great degree, as programming tends to do.
I can't see where you had either kind of operation then just suddenly lost it except by the program method, then it would have to be backed out by reverse programming, back to stock. This does not just happen by rebooting the PCM with a powerdown because the PCM does not store a seperate copy of it's original programming to come back up running on.
If you investigate tuners, you will find that a copy of the program lines that are alterd are indeed stored in the tuner so it is there to be put back into the PCM when desired because those program lines in the PCM are 'overwrittten with modified lines the PCM uses to shift the trans with the new intended firmness and rpm points.
IMO you are into wishfull thinking in trying to get back what you thought was good shifting.
There is always a remote chance that there is a fault at the valve body that contributed to the shift firmness. An example of that would be a broken spring in the valve body that can cause an accumulator to move faster causing a firmer shift for that gear or a fault that raised system pressure by some means or even wear caused changes in shifting.
I hope you get satifaction but this is about how it works in reality.
Let us know if something is found.