question on gas mileage and boost..
 

Well i got my 94 about two weeks ago..and ive only driven it a couple times...anyway when i fill up the gas tank i only go about 120 miles is that normal or what the hell is the problem..also it boostes at 11psi until i hit 5000 rpm then it gradully falls ...by the time i hit 7000 its fallen to 5psi.. whats the problem

clogged cat? I get aorund 220 miles ot a tank. With pump, PMS, turboback exaust, etc....

I actually just put a downpipe on it because it was clogged...so it breaths fine now..

how much gas are you putting in? I get around 220 - 250 miles and usually put in about 15 gallons. If you're putting in much less than that, maybe you have a faulty gas gauge. I've got a K&N, DP, Cat-back, & M2 ECU.

Brian, do you drive a silver fd? Were you in the San Gabriel valley today (1-20-03)?

-Hex

Did you change your plugs, air filter, fuel filter, o2 sensor, oil yet?

so
does a clogged pre-cat afftect the boost level???

Yes a clogged precat affects boost (lowers it at higher rpms). I noticed a big jump in gas mileage by replacing the plugs and getting the vacuum system all checked out (partial hose job). Now I get 19mpg (320-350 miles per tank) in mixed (mostly highway commute) driving. 120 miles to a tank is awful unless you're putting in half a tank, or driving at WOT up and down hills all day. The lowest I've recorded was 11mpg (thats still around 200 miles if you fill up at the E) and that was with very aggressive driving. I suggest first replacing the plugs and wires, and check the computer for codes. You might have a bad thermosensor that is messing up the mixture. Also replace the air filter if its old, that can hurt mileage as well.

repost

hehe... just saw this, but uhhh, yes I do and no I wasn't - I don't drive my car during the week unless there's some special occasion & the 20th wasn't anything special. ;)

u know what, i got 260km/65 L of 92
i think mainly becaz of mulfunction O2 sensor
second reason maybe becaz of clogged pre-cat caz i always hear pop sound when the idle is hunting from 800~1200 rpm
third reason i suspected would be old spark plugs~