about 220 on a tank. 99 teg ls. i was getting 300 on a tank. regaped my plugs to .44 (stock ls gap) and gas mileage started to go downhill.

 

Try doing some maintanence, such as changing your fuel filter and using a bottle of fuel injector cleaner.

 

220...that sounds like my car! except I don't think I've ever gotten 300 other than road trips. a lot of people keep saying oxygen sensor, but I think the fuel filter is another culprit.

 

will check... its been like 20k since i changed it i think. i just put new plugs in. i know my o2 sensor is faulty but it hasnt hindered my gas mileage before, well atleast i didnt think so. i put the stock air filter back on. but its on my sr intake. buti was getting the bad gas mileage before that

 

one of my friends had the same problem. the problem was a crimped fuel line. a rock had hit and bent one of the metal lines. if you check ur fuel pressure and match it to a manual u can see if that is the problem. maybe

 

THIS GUY IS A ******* SCAMMER!!!! DONT HELP HIS SORRY ***>>>SCAMMED ME OUT OF A HUNDRED DOLLARS!!!!

 

Is there any hesitation or is you check engine light on? The O2 sensor will cause hesitation and throw a check engin light. If not I'm going to lean towards the fuel filter.