Fuel mileage tuning for 2000 GTP?

[ravenp]

Hey folks. My wife drives our GTP as her daily and while she loves the power, recently she's thought of trading it in because of the terrible fuel mileage particularly in winter.

We live in Canada so I dont' know the MPG we're getting but we struggle greatly to get 400Km's to a full tank of 94. On a trip to North Carolina last year I got at most 530km's to a full tank purely highway driving and light on the pedal.

From my investigation on a local Gp/GTP board, this is normal for these cars, so what i'm wondering how easy would it be for me to tune for better economy and just how much of an impact there would be. I'm comfortable using HP Tuners(if i know what to change and to what values) and have this car as an option to tune.

Opinions?
thanks

[coachcrow56]

Scan your GTP and see what your LTFT's look like---you want them close to 0 at idle and at cruise. Adjust your MAF slightly (leaner) and see what it does to your LTFT's. You can also bump up your timing, but watch your KR.

[Russ K]

I would turn off the egr, just set the iat temp to 140 C
For short trip driving, lowering the closed loop temp
and reducing the delay time helps. On your car at 10 C
there is a 50 second delay to enter closed loop.
It would be nice if the V6 cars had O2 switch point
tables like the V8 cars to lean the closed loop afr.

You could also add some low cyl air timing. Removing
the cat convertor and the u bend would help power
and mileage. If you have to pass an emission test a
high flow cat and u bend eliminator pipe is a better
choice.
These cars are quite rich at wot, so tuning with a wide
band O2 is a good idea.

Russ Kemp

[jjnada]

You might be able to try some things mentioned in this thread: http://hptuners.com/forum/showthread.php?t=4929

[Russ K]

That thread is mostly for V8 engines, the V6 vehicles don't have any tables for DFCO, O2 mv switch points etc.

Russ Kemp

[ravenp]

Thanks guys.. I appreciate the help. It's such a pig even on the highway. The wife is considering trading on an Accord to get a 5speed so i'm trying my best to dissuade her