After loading a modified LS1Edit file I noticed how the fuel trims made a +5% jump.
From a scan I would say the MAF calibration has changed.
The thing is that I changed a completely differet thing (fan ON-OFF settings)!!

I double checked the program and every fuel related table is unchanged.

No error codes.

Is it possible to make something wrong while loading a file?
This is a 98 Trans Am PCM, LS1Edit software and interface come directly from Carputing and I used them xxx times without problems.

I just remember one thing: when the program has been loaded the software tells you to turn off the ignition, close the "Prog Load window" and quit LS1Edit.
After that I usually disconnect the interface and start the engine.
This time I've started the engine BEFORE unplugging the interface.

A couple of days later I re-loaded the same program and (MAGIC!) the fuel trims are now where they used to be.

How is it possible?? Is it a problem when starting the engine with the interface plugged in?


Thanks for any comment

Stefano