Did a recent tune up and still have really bad gas mileage

[ibanez]

Hey everyone, so I'm having a problem with my 91 240sx coupe that i just bought a month ago. It's an automatic if that makes any difference. I only get about 200-260kms per tank. I recently changed the following things:

distributor cap and rotorspark plugsspark plug wiresfuel filtero2 sensorwater temp sensor

oh and i have a drop in k&n filter in there right now that looks to be clean.my car runs really smooth yet i seem to be running out of gas quite fast. Even after the little tune up my gas mileage hasn't changed.

I do have some pretty bad snow tires on my car right now that were somewhat ruined as they are directional snow tires and the previous owner had put the tires on backwards and the mechanic told me the steel belts are messed up now. because of this, my steering wheel shakes when i drive. the wheels were rotated so they're on the right sides of the car now but the steering wheel still shakes a bit. i'm sure this would harm my gas mileage but would it affect it this much? i've searched the forum and see that some of you are getting 300-400MILES per tank and i'm only getting about 250KMS! which is about 155miles.

anyone have any ideas?

thanks.

[Pollarican]

I would check your FPR (Fuel Pressure Regulator.) There aren't many things that can dramatically affect milage like the way you are being affected. If the FPR is your culprit, chances are you can smell your car running pretty rich.

[Shift_Tommy]

check timing,gap spark plug,run ecu testand seafoam the car

[thatdudety]

what about intake filter?

[180fan]

Recalibrate your TPS? Might also want to check over your injectors for any leaks. Also check over your timing.

[S14-KOUKI-MONSTER]

what about intake filter?

Um, I don't think so.

It wouldn't hurt to clean your maf sensor either. I use the crc maf cleaner. But that's alot of fuel to be going through. Like 180fan said, check for leaks.

I live in BC too, and own an Ibanez.

[ricebike]

that steel belts that r messed up soo much... if your steering wheel is shaking that much as well, it may also be tripping the knock sensor too!

retarding timing & power & well, u get the drift...

did u test the ECM for any trouble codes? doesn't hurt to know...

[skylinekin]

i get 18-20 mpg, before I changed my o2 sensor I was getting 12 mpg.

[240Guroo@ProtoMotoring]

check timimg. set it within specs with distributor and timing light.

yes the k&n ail filter unit will change gas mileage. it will dramatically cause more air flow while ecu will automatically adjust and try to dump more fuel in there.

snow tires can almost drag the car down forcing it to work the motor a little harder and therefore cause lower gas mileage.

this is just basic things you can check that are easy to do to. there is a bigger picutre to look at. like fuel problems, and sensor problems. start with easiet things and basics.