Help 7.3 missing, no codes, did buzz and contribution tests

[Probuilder]

I have the FU chip and burner in a early 99 7.3 F 250- With DAC2 PCM.
I installed the chip and everything worked great for about 2 months.
I decided to reprogram different tunes on the chip, and change the order of them. When I reinstalled the chip everything seemed ok but I didn't try the 1200 rpm Hi Idle tune, until I was jumping hooking up my 18' car trailer, tune used to get he truck warmed up a little faster.
Once I switched the chip back to Heavy tow, the truck started missing on idle and all the way up through the rpms. EGT's were about 400 degrees higher than normal, running 1200 degrees running down the road @ 60mph on flat ground.
When I reprogrammed the 6 pos chip I didn't put the stock tune on it. I shut the truck off and reprogrammed the chip again, and just removed the one program and reburnt the stock program on the chip.
Now I have tried to remove the chip, while in stock setting, and then check for codes, I come up with nothing, no codes at all.
So I took the truck to a ford garage, after completely removing the chip from the PCM, they can't come up with any codes that are stored either and no pending codes.

Ford garage did a contribution test, #3 and #8 are only contributing 80% but the buzz test is perfect.
They told me that it was because of the chip tuning??????? That something was loaded wrong????? Is Ford right? I know the PCM is a DAC2 and we are installing DAC3 tunes to the chip????????

What do I need to do to get this truck back to stock, and running right?
I need to use this truck to pull my 34' and 16K goose neck construction trailer Tomorrow.