Limp Home Mode

[Sburn]

I had this happen yesterday after adjusting canned tune #2, 87 towing. To help Bill track this one down, here's the info:

2007 4.6

Had been running #2 tune for a few days with no custom changes and no issues. I then made a couple of changes from the base program:

Idle speed +75 (this seems to help driveability in parking lots)
WOT enrich 1.3 -> 1.5

Gear ratio from 3.73 -> 3.55

The canned tunes all seem to default to 3.73 even though my truck has a 3.55 (axle code 19 on the door sticker).

Tire size from 237X to 2337. Like gear ratio, canned tunes seem to start with very slightly incorrect values.

Not from a full cold start -- off for about three hours, but mostly warmed up (~160 degrees CHT). Taking off from a stoplilght, about 1/3 throttle, ETC light and loss of power hit right around 1-2 upshift. No CEL light.

Limped a few blocks to a parking lot, shut off. Key on, diagnostics, DTC P061B only. Returned to stock. Hit the drivethrough and back to job site on factory tune with no issues.

Back to PHP #2 tune without mods (load previous settings = NO) for the trip home (50 miles) with no issues.

Hex code and serial number should be in my profile.