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gas mileage

My 98 GTP is getting 27 highway, and about 20 city with 198k on it, and my 08 GXP is getting about 21 Highway (kind of a stretch) and City is about 16.
 


I've been getting about 19-20MPG consistently in my '98 GT since I now had OD again. 20MPG is with more highway than normal. Not too impressive, but cheaper than my TBSS and I can run 87.
 
my mpg also sucks, i get approx 17.7 mpg, and if the specs of my car are right and i have a 18 gallon tank, when 13.5 gallons are used its on the line of E, i also dont have overdrive so it only goes up to 3rd gear which is a gas killer, thankyou GM for not making our 4th gearclutch hardened, we're reaping the benefits of our 4th gear splines after 120k :th_thumb-up:
 
danielle15 said:
Right now, I'm sitting at 320 with still a bit over 1/4 tank left. Lately its been getting really good MPG's. I can normally get 23-24 (27+ pure highway) out of it doing mostly rural driving. And I'm pretty light on the pedal. Overall, your numbers are very close to my GT's.
I did run some sea foam thru just the gas tank and it did seem to help a little bit.
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I'm right along with you Danielle, that's one of the reasons I joined, to get an idea if what I'm getting is close to average or possibly better. Pleased to meet you all!
 
I've been average 15 or so on the DIC all city in my 2002 GTP. While it has been reasonably cold, should I be checking for problems? Or is this par for the course?
 


I wouldnt worry.

I just hit 125 miles on this tank, already used 10.8 gallons and just hit the 1/4th tank mark. I drive all city, less than 7-8 miles most days. I bet I waste half my tank from idle time.
 
so i have an '04 GTP. Only Modifications I've done are a k&n Air Filter and my brother put in a Vortex semi circle spiky contraption (sorry i dont know what its called anymore it was 5 years ago) in the air tube that feeds the engine. As far as gas mileage goes my car does amazing on highways i can drive from Miami to Orlando in about 3/4 of a tank. If i remember the last time i ran a trip meter on the DIC it was about 300. However in this godforsaken city im getting about 13 - 14 MPG with a light foot. Sometimes less if i drive a bit harder. Is there anything i can do to improve that?
 
so i have an '04 GTP. Only Modifications I've done are a k&n Air Filter and my brother put in a Vortex semi circle spiky contraption (sorry i dont know what its called anymore it was 5 years ago) in the air tube that feeds the engine. As far as gas mileage goes my car does amazing on highways i can drive from Miami to Orlando in about 3/4 of a tank. If i remember the last time i ran a trip meter on the DIC it was about 300. However in this godforsaken city im getting about 13 - 14 MPG with a light foot. Sometimes less if i drive a bit harder. Is there anything i can do to improve that?
 


sorry for double post not sure why it did that. My brother said that its supposed to improve hp and mpg. throttle body has been cleaned recently and not sure what a maf sensor is sorry im not exactly car savvy. i know some stuff but not everything and usually anything i have to do to it, i take it somewhere to get it done. i havent had any check engine lights yet so not sure about spark plugs so far i have 56k miles approx.
 
I changed my plugs / wires and am only getting 22.9 mpg highway. Used to be higher...I posted 21.3 above, but meant 23.1. Mileage has been dropping about a tenth of a mpg at a time over a few months. Wonder why the slow decline, even after new plugs & wires?

Steve
 
Comanche1959 said:
I changed my plugs / wires and am only getting 22.9 mpg highway. Used to be higher...I posted 21.3 above, but meant 23.1. Mileage has been dropping about a tenth of a mpg at a time over a few months. Wonder why the slow decline, even after new plugs & wires?

Steve
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Might be another issue. Depending on age of the car it might need somthing else. Could be a o2 sensor or the cat converter giving bad readings to the rear o2 causing more fuel to be burned. Drive the speed limit or under and increase mpg by alot aswell. Its truely hard to figure it out over the internet.
 
I see why its not suggested to run AL104s on stock pulley and tune cuz my mileage has taken a noticable hit. Im getting around 20-30 less miles per tank compared to my older plugs. Hopefully it picks back up once im tuned otherwise might just get a fresh 605 plug along with the other ones i have and swap those in.
 


Fivefingerdeathpunch said:
I wouldnt worry.

I just hit 125 miles on this tank, already used 10.8 gallons and just hit the 1/4th tank mark. I drive all city, less than 7-8 miles most days. I bet I waste half my tank from idle time.
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Cool. I'm about the same range with an additional trip to and from the gym most days. It's decent on the highway. Driving from Chicago I want to say I was around 24. I didn't buy a supercharged car and expect awesome gas mileage.
 
Keep it under 2k rpms when maintaining speed.

And hit the catalytic converter when it's cold, any rattle means you should replace it
 
Fivefingerdeathpunch said:
Might be another issue. Depending on age of the car it might need somthing else. Could be a o2 sensor or the cat converter giving bad readings to the rear o2 causing more fuel to be burned. Drive the speed limit or under and increase mpg by alot aswell. Its truely hard to figure it out over the internet.
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I drive the speed limit on my daily commute of only 11 miles one way over rolling country. May try the O2 sensor.....easy enough to do.

Thanks,

Steve
 
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