HAUS

when i first got my car i was getting about 200-220 miles per tank. now im getting any where from 150-170 MPT. why and how did it change so drastically and how can i fix it.

Chopper

Fill the tank up all the way untill you get gas up to a repeatable level in the filler neck .Then drive it normally untill below 1/4 tank and refill to the same level,preferably at the same pump,then figure MPG.Sending units are not accurate especially over time.Gear changes,tire size and bad plugs and wires, air filters,even driving in adverse weather can pull down gas mileage.Good luck

HAUS

thanks for the ideas. has stock tires, stock gears, air filter is clean. so ill try the plugs and wires cause i believe the wires are stock and the engine has 150,000 miles so ill check the plugs. thanks for your help

NeoTokyo

your O2 sensors could be going bad or not reading correctly. O2 sensors are expensive so make sure before you change them. Usually the Check Engine light would come on if some thing were screwy with them.

98LS1

If the O2 sensors are messed up the car will be flooding most likely. When you start the car check for a strong gas smell from the exhaust pipes and black smoke. If it's none of these, stay outta the throttle.

TheGmKiller331

If you are running on 150,000 miles on OEM equipment you need a serious tune up.Try plugs and wires,cap and rotor.And if it doesnt improve change your 02sensors as well.Depending on how long you have been going like this and how hard you have been beating on t you may or may not need the o2 sensors so try the tune up first.

NeoTokyo

Your looking at about $60 dollars per sensor and there are 4 of them. Good luck!
Plugs are cheap, dont bother with the multi-point plugs, they are **** and the Bosch +4 prongs break off sometimes and really mess things up. Iridium is the best way to go right now so get some of those. NGK makes iridium plugs I think, check their site out. Also those BOSCH +4 run hot and put excess stress on your ignition system.

TheGmKiller331

Yeah i wouldnt start with o2 sensors thats why i said go with a tune up if that doesnt do it try the next obvious.Let us know how that goes.



And nothing beats a motorcraft plug or a autolite.

NeoTokyo

Aye, Im using Autolites right now Mine are ( AP 2545 ) Yours probably will be the same. If your old plugs are really bad like capped and burnt then take pics for us [8D]


-Neo-

TheGmKiller331

Yeah pics are always great.

And i can tell you from experience that those 4 prong bosch's suck *****.I wish i would have gotten a pic of a friends LT1 when they broke off his.Man the piston looked like someone took a hammer to it.