poor gas mileage 2005 gtp

[pippin33]

I recently bought a 2005 gtp with 28000 miles. I use 91 oct. fuel, changed the air filter and still only get 12-14 mpg city. I have also tried babying the piss out of it no luck and no fun either. Am I expecting to much to get at least 17 mpg?

[BNaylor]

Isn't the fuel economy for the '05 GTP supposed to be rated at 18 city/28 highway?

I don't think you're expecting too much. Your current mileage is in SUV territory. How's the highway mileage?

Hopefully some of the few guys with 04/05 GPs weigh in.









Thrasher CAI, DHP v1.0 PCM, SLP Headers,
3.25 SC pulley, CAIT GMAF, 2.5 DP/Hi-Flow CAT,
u-bend delete, 160 TS, ZZP Stage 1 72mm TB,
TB spacer, MSD 8.5mm wires, Autolite 103,
Goodyear Gatorback Serp. & SC Belt,
Nitto NT555R Drag Radials
1/4 ET: 13.210 sec. @ 104.490 mph
0 - 60 ft: 1.945 sec.

[damuleman]

The 2005 Grand Prix is suppose to run on 93 octane only (Preimum Only). If you are going to run (91) use a octane booster additive. I know the high cost of fuel is making us all wanting to use cheaper fuel. But that solved my wifes problem in her 2005 Grand Prix. She now gets around 23.5 mph in the city 28 - 30 Hwy

[bbrock]

I use 93 octane and get about 17-18 mpg (city), but I don't drive it nice either.

It's a 2005 GTP, no mods.

[bbrock]

Originally Posted by damuleman

The 2005 Grand Prix is suppose to run on 93 octane only (Preimum Only). If you are going to run (91) use a octane booster additive. I know the high cost of fuel is making us all wanting to use cheaper fuel. But that solved my wifes problem in her 2005 Grand Prix. She now gets around 23.5 mph in the city 28 - 30 Hwy

This isn't a GTP is it?

[pippin33]

Originally Posted by damuleman

The 2005 Grand Prix is suppose to run on 93 octane only (Preimum Only). If you are going to run (91) use a octane booster additive. I know the high cost of fuel is making us all wanting to use cheaper fuel. But that solved my wifes problem in her 2005 Grand Prix. She now gets around 23.5 mph in the city 28 - 30 Hwy

91 oct. is the best fuel they sale in San Diego. What octane booster would you suggest?

[Dullboy]

Originally Posted by pippin33

I recently bought a 2005 gtp with 28000 miles. I use 91 oct. fuel, changed the air filter and still only get 12-14 mpg city. I have also tried babying the piss out of it no luck and no fun either. Am I expecting to much to get at least 17 mpg?

I've used 87, 91 and 93 octane gas in my '05 GTP and the gas mileage has been pretty consistent. You can use 87 octane according to the manual, but with reduced performance. My salesman told me the same thing. With mixed city/highway driving I average 24mpg. I've never gotten less than 20mpg.
I hope your mpg's get better. With these gas prices, that's gotta suck.