cause i get 17.7 max and shouldnt it be better?

If that's your around town I wouldn't sweat it. If that's after nice long highway run then you have issues.

2000 L36
OE: max of 30mpg highway

CAI, HV3, NEW complete suspension and ResponsEdge tires: 32+ mpg

sorry that I cant produce the proof, but these were the numbers my wife and I were reporting between ourselves.

?

yea thats highway

in town?

OE: ~18

not-stock: ~23

no my gtp jsut has a K&N interchangable air filter which i think is dirty but yea thats highway about 17.7 so thats bad?

Id say so. unless its mixed-condition driving, a combination of highway and city, then Id expect mpg to be really off like that. throwing any codes? performance sucking? suspension and tires old and worn out? when was the last time you did a GOOD tune-up? what quality of fuel (not talkin octane here) are you using? how dirty IS that filter?

it is kinda mixed but its more of a long drive like 1 1/2 hours there and back once or twice a week and thats what the mileage is. there are no codes ummmm performance seems normal suspension is stock but doesnt seem worn out i have new tires from this year. what do you mean good tuneup and what do you mean quality of fuel? and the filter is pretty dirty i might just go and buy a different one cause i dont have the spray for the k&n

good tune up: GOOD wires (not the house brand from AZ or something), GOOD plugs, check all sensors, vacuum line check, sensors seated well.

if you use a mom-and-pop stop for fuel, you run the risk of high dirt and water content. a leading chain has better tanks and filters, as well as the fuel stores constantly being refreshed. that's opposed to a small, podunk stop keeping the same fuel on hand for a few weeks. a few years ago AAFES had poor quality fuel, even though the octane was the same as civilian outlets. consider fueling at shell, texaco, etc. if you dont already. if you already use a major chain, disregard the above ramble.

the cleaner and oil for your filter is like $20 at AZ or Advance or almost any other parts house. it comes as a kit, and the kit is normally good for a year or more worth of cleanings.

i get my gas from bp and what octane should i use 91 is the highest and ive had the car for 7 months and havent gotten a tuneup and and what does this oil thing do?

if you're running a stock GTP, you can run mid-grade. once you start to mod, then hi-test is required to kill KR. if you want more info on that stuff, Im gonna hafta defer to one of these blown guys.

so if i did mod my gtp it would be bad to jsut have 91 octane

Run the highest you can get.

Not sure on the altitude where your at but high altitude locations will have lower octane fuel available then those at sea level.

example
91 in Denver is equal to 93 in LA.

The oil thing he is talking about is for the K&N filter. You clean it with the supplied cleaner and you have to respray the filter with oil otherwise the filter won't filter jack squat.

okay the filter is super dirty there is basically a black circle in the middle and thats it