I have a 89 honda prelude and i love it and i was getting great gas mileage and then all of a sudden iam only getting like 130-150 miles on a full tank of gas my uncle thinks it may be the O2 sensor bt does anybody have and suggestions i need help gas prices suck right know

 

UNLESS YOU ARE MECHANICALLY INCLINED, I WOULD TAKE IT TO THE DEALER, AND HAVE IT PROFFESSIONALLY TUNED!!! YOU'LL HAVE PEICE OF MIND, AND A BETTER RUNNING CAR, AND THATS WHAT MAKES DRIVING FUN!!!

 

Don't take it to the dealer you'll end paying more than what the car is worth, get a haynes or chilton repair manual run the codes and then post what it says.

 

you could go to the dealer....but only for there manuals. around 100 or so. specifically for your car and year. those troubleshooting charts are the easiest to understand. well worth the money if you wnat to keep your car running.
without knowing more about your car......fuel filter, air filter, air pressure, driving habits, o2 are all possibilities. any check engine lights?

 

Sounds like the car could have reverted to some sort of safety setting.
Get the diagnostic codes checked as others have said. Id prefer not to go to a dealer (or stealer a si sometime call them) if possible and have all the work done.

 

be careful with the "stealer" comment. most of the people on these forums ar mechanics and or work at the dealer. if you did take it to the dealer they would charge somewhere around an 80 fee for looking at your vehicle. they should tell you whats wrong and then you can go home and fix it yourself. sometimes it is worth that charge.

 

Quite right mate - appologies to anyone who may have taken offence to my previous comment. I have had a couple of bad experiences recently, however that shouldnt mean I tarnish all dealer's/ mechanics with the same brush.

Ive been charged for new ECU's when it only needed a minor repair (and thats all they did ,Charged £800 but it cost him £72 up the road at a local auto electrician) and been charged for new calipers which didnt need replacing and were not actually changed - just cleaned up slightly. (i marked them with small dabs of paint as I was suspicious). This was a dealer that had been recommended through my club and was doing a roaring trade in servicing mx-5's (Miata).

Maybe I should thank them, as it what has spurred me into learning a bit more about my car.