Got 28.3 mpg average on the GT2000's maiden voyage to Chicago from Des Moines, IA. Just wondering how you guys do on mileage. I am thinking about doing the U bend delete, a high flow cat, and a new fuel filter. Any other suggestions to increase my mileage would be greatly appreciated.

With all the mods in my sig i top out at 34mpg the best hing to do is open the exhaust and let her breath easyer. Or in the words of drummerboy , i think, let it breath better and fart better...

The only thing I want to stay away from is loud exhaust. I don't really know of any good high flow mufflers that aren't loud.

you really dont need them. the manifolds are horrible, especially the front one.

just stick with the stock muffs. go with a 3in DP, Headers, and u-bend delete

Will headers help or hurt my mileage? I've heard both ways with different cars.

Yep, that was me!

I just took a trip to St Louis in my GP (approx. 500 miles round trip) and even all the highway driving I did, I only averaged 22.6 mpg. I think it's cuz of my torque converter being screwed up, because I know it should be higher than that. Anyone have any other ideas?

Well for N/A applications, I beleive, Headers aren't good for gas milage for our cars b/c you loose some of the back pressure needed for the eninge, the best thing for N/As is some nice ported manifolds and a D/P.

it will help you. I dont know how it would hurt. But with an N/A car. PEMS might be the way to go. You dont want to lose all of your torque

I've been doing my research and people are saying that only the front one will make a noticeable difference due to its design. I guess that the rear manifold flows enough unless you're blown. I'm thinking that it is a lot easier to replace the the front by itself also.

Yes the front manifold is way more restrictive then the rear. The rear is almost like a header. You can port the front manifolds. But to do so you'll need someone to beef up the welds because once you start grinding away on the inside to open up the inlet you will remove most of the factory weld.

i average 15 in the city.
i have a vacuum leak that im waiting for a warm day to fix

Another option instead of a ported front mnfld. is ZZP's power log, it adresses the problem front mnfld. and is similar in design to the factory rear mnfld. .Chico.

I've topped out at 34.8 hwy and had a low of 13.6 due to special circumstances .. All stock 02 GTP, save for a CAI.

Ok, ya'lls 30+ MPG is ticking me off. I have a friggin 3.1 and only geting 21 with a mix of highway and city.

That's hacking me off too! hah :rolleyes:

My 3100 depends. Worst I've seen is 24, best is right at 30mpg. The latter is with a lot of I-75 travel, but there are a lot of hills between here and Richmond making for a lot of downshifts.

going up north i was averaging 34.1. Drafting a semi - - 38.6 hehe

I can get about 28 highway most of the time, but I sure would like to get 30+. My '98 GT is stock, with the exception of MSD plug wires. Any thoughts on how I can push the MPG up in the 30 range would be greatly appreciated!

I think I am going to just start driving like a grandpa and not do over 35. I'm sure gunning it at lights is not helping mine what so ever, or my transmision :rolleyes:

GOSH SOMEONE NEEDS TO HELP ME OUT lol i am only getting like 17mgp thats basicly all in town driving and about 40 miles round trip out of town every once and a while. i need some searious help though if everyone is getting high 20s to mid 30s

im only getting around 17..but it is time for a tune-up

sounds like i need one too

I get bad MPG in town, although I haven't checked it closely. Most of miles are highway commuting, and the only way I can get high mileage is to drive about 5 mph slower than everyone else, stay in the right lane, and use the cruise control. That way I can maintain a constant speed while I watch everyone else bobbing, weaving, speeding up and slowing down.

We actually did an unscientific comparison a few times....people we work with would blow by us in the morning at breakneck speed...we'd stay in cruise mode. They'd be just stepping out of their cars as we pull into the parking lot.

I'd still like to get 30 MPG, just once....

Best I've gotten in my 3100 is 26MPG mostly interstate. Lately with all this cold weather and city driving has killed it...I got 15.8MPG at one point . Then there's my mom's 3100. Her "bad" is 24MPG, normal is 25MPG and best I think is 34MPG. But it doesn't get up and go like my car, maybe thats why...

I just filled up last night... avg'd out to 16.9 MPG. That's so bad... geez

I should have mentioned...I have the 3800 Series II engine in my car.

Those of you who have been posting their MPG, do you all have the 3100? Just curious.

15.5 This things is a HOG!

when is it time for a tune up? i have a '03 gtp with 57,000 miles. What should i replace for my tune up?

Depends on the car and the plugs used. The plat or iridium plugs normally are somewhere in the 75k to 100k mile mark. Copper plugs I believe are closer to 5-10k miles mark.

For a tune up, I would...
Replace plugs and wires
replace air and fuel filters
Change transmission fluid
check brakes
flush radiator, change to green, replace thermostat.

Depends on whats been done to the car already too.

Jesse

where is the fuel filter on our cars .... 99 gp gt and ... u said change rat fluid... dont u have to use dex cool with our cars .... i dont think dex cool is green?? idk just wondering?

It's behind the driver's side rear tire. I didn't even jack it up to change it, but it would help.

Yes, they came with Dexcool, but most people (like myself) had it flushed for the green stuff. Dexcool will sludge, gel, and screw up gaskets if given the chance. The green stuff won't, plus it costs less.

thanks for the info jjcom! i already did fuel and air filters, and im changing the antifreeze and transfluid in the warmer weather...but i appreciate it
-dan