04 GTP Bad Fuel Economy

[pr84704p]

Hi guys, I know there are lots of threads in the forum about this, but i did not find what i was looking for. I just bought the car a few days ago and I am concerned about the gas mileage the DIC is showing me i am getting. When i set it to readout the instant fuel economy, it is horrible. Like 13 everywhere i go unless i am cruising barely touching the gas on flat highway at 55 or more and it shows me maybe 20-23 MPG. Average MPG says 13. I reset it a few days ago.This is certainly not what i was expecting. Car is running great, only has 38K on it, and Oil life is at about 96% I see people are saying replace the plugs and filter and all of that, but shouldn't the pugs be fine considering the mileage i have on the car? I would appreciate any help you guys can give me. Thank you.

 

[cerick08GP]

Well, first off don’t freak. GPs actually get great mpg for a mid sized car. Well, the N/A ones do, the GTPs get like 2 mpg less than great.:th_winking: Secondly, the DIC mpg avg read out is usually close. But you can’t take for 100%, and the instantaneous read out is all over the place on any car. Track your mpg the old fashion way and see what you get. Also, it is winter, all cars get crappy mpg in the winter, especially on short trips until the engine is warm and the tranny can lock up. If you getting 23 mpg on the highway your probably looking before your warmed up, wait until the tranny locks, then look. If you track your mpg in normal city/highway driving you should be at about 20-21mpg. I have a few questions for you. #1 Are you using premium gas? Because if your not you WILL get crappy mpg. #2 Does your car have stock size tires? #3 Cars get zero mpg in park, how long do you warm up your car?

 

[pr84704p]

Well, first off don’t freak. GPs actually get great mpg for a mid sized car. Well, the N/A ones do, the GTPs get like 2 mpg less than great.:th_winking: Secondly, the DIC mpg avg read out is usually close. But you can’t take for 100%, and the instantaneous read out is all over the place on any car. Track your mpg the old fashion way and see what you get. Also, it is winter, all cars get crappy mpg in the winter, especially on short trips until the engine is warm and the tranny can lock up. If you getting 23 mpg on the highway your probably looking before your warmed up, wait until the tranny locks, then look. If you track your mpg in normal city/highway driving you should be at about 20-21mpg. I have a few questions for you. #1 Are you using premium gas? Because if your not you WILL get crappy mpg. #2 Does your car have stock size tires? #3 Cars get zero mpg in park, how long do you warm up your car?

I had a half tank of gas that the dealer had put in. My guess is that they put in regular, but i can't be sure. I filled it up the rest with 93 octane today. The car has hankook optimo tires on it, i am not sure if they are the same size as stock, but my guess is they are stock size. It has the stock rims. I have been warming the car up 5-10 minutes before driving.

 

[cerick08GP]

I have been warming the car up 5-10 minutes before driving.

I knew it. Even on the coldest day, two minutes max buddy. Not only is it a huge waste of gas, your tranny stays dead cold. Dress up warm, don’t let it idle more than a minute, drive slow at first, low RPM is more important than actually speed. Since you don’t know your car yet, be aware you not going to get max mpg until both your tranny and coolant get warm. On my car the tranny won’t lock up until ~90F, that alone is good for 5 mpg on the highway.

 

[pr84704p]

I knew it. Even on the coldest day, two minutes max buddy. Not only is it a huge waste of gas, your tranny stays dead cold. Dress up warm, don’t let it idle more than a minute, drive slow at first, low RPM is more important than actually speed. Since you don’t know your car yet, be aware you not going to get max mpg until both your tranny and coolant get warm. On my car the tranny won’t lock up until ~90F, that alone is good for 5 mpg on the highway.

I gotta try only keeping it on for a couple minutes then. I did not know that would affect the mpg negatively. I think i was doing mostly everything else right. Thanks for helping out.

 

[pr84704p]

Could the DIC be off also? Because even with warming up the car too much, it should be above 12! Thats ridiculous.

 

[cerick08GP]

Well, the DIC could be off. Especially if you haven’t got stock sized tires, they will throw it way off. On my car, the avg mpg seems off by ~1 mpg so far in my tracking. Let me put it straight, first off you bought a super charged car! Every S/C car in history gets lower than the standard versions. I can almost assure you that your car is top notch, how it is driven accounts for +/-30% of most people’s mpg. Historically an N/A GPs gets the same mpg as the V6 Camary, so if you think you bought a bad car. Go trade it in, get a mid sized 04’ ricer that will get about same mpg, but have about 80 less HP and be happy again.:th_tongue2:

 

[PH04GTP]

cerick08GP is dead on. 5-10 minute warm up will kill your mileage. I usually only let my cars warm up for a couple minutes, and only if the temp is 20 degress or lower. Cars today don't need a warm up period like the old carbed vehicles did. They are designed to be started and driven. That being said, just follow what cerick said, drive conservatively until the vehicle warms up fully. I usually try to keep it under 2500 revs until the car is fully warmed, usually about 5 miles or so. On S/C car 2500 rpm should also keep you from pushing alot of boost down a cold engine. This works for me, and I usually pull 18-19mpg in the winter and 22-23 in the summer with mixed highway and city.

 

[TorqueAutoMotiv]

The dic mpg is touchy is your not used to it reset it drive a normal day with out the long warmup period and let a couple days of driving register to get an acurate average

take offs use the most gas per mile so to speak and idleing is a negative mainly because your not traveling so it kills your average on miles traveled versus gas used

you should be getting around 16-18 city and 25-31 freeway depending on how you drive

 

[pr84704p]

Thanks guys, i noticed a difference when i stopped warming up the car. It is really cold here in new york and after a few days now my average has gone up to 18-20. Hopefully it will go up more in the warmer weather. And no, i love this car, i would take this over a camry any day! :th_biggrin2:

 

[ZR1Vette09]

told ya always make sure your tires are inflated right and you aren't a lead foot. I actually trick myself sometimes, if i push higher up on the pedal where the spring is taking most of the force i'm pushing just as far but not accelerating as much.