The hunting should be easy to fix. Just a minor shifting inconsistency.

As for the performance, the 2006 may be rated the same for final output but the torque management strategy is completely different and results in a higher net output on the 2006 vs. the 2004. Also, the PCM uses load based calculations to determine how much power to actually produce so a slightly larger tire will actually translate into a slightly higher load and the PCM will let the engine produce a little bit more power.

To further illustrate this point, we had a customer that went to a shop that installed 4.88 gears in the truck thinking it would improve launch and acceleration. What ended up happening is that that load on the engine was so drastically reduced with the new gears that the truck ran slower than it did stock. Talk about an expensive mistake.

Because these calculations take place in the actual "program" or "software" part of the calibration, it is not something we can remove. We can change certain aspects of the output by modifying the throttle control mapping and other functions, but the fact remains that the less load there is on the vehicle the less power it will ultimately make.

I hope this make enough sense. In any event, we'll need to look into the shifting issue. Get with me tomorrow and we'll be happy to get it worked out

Take care.

So does the '05 F150 function like the '06 or the '04 in terms of load vs. power?

All the ETC vehicles handle power output based on load. I couldn't say for sure if the 05 is more like the 04, the 06, or somewhere in between. I'll have to see if I can dig up some 05 dyno plots.

:D

Okay. Let me know what you find when you get a chance.

No I dont think it is hunting between gears, and only happens once and awhile.

Anything yet Bill?