what could lead to bad fuel economy

[ClearCoatMiata]

ok so when we were leaving from porkys to eriks one day i burned about quarter tank of gas which is alot for going from porkys to eriks i have changed the spark plugs befor this episode happened , it did throw me a code one day but it hasn't came up again, im thinking its the o2 sensors both of them, and im guessing the MAF mabie i dont know whats your guys oppion on this.

 

[dmention7]

I would blame the notoriously inaccurate fuel gauges before I rush to any assumptions about a problem. Check your milage over at least a full tank using the actual miles driven and the actual fuel consumed.

Many gas gauges will vary by as much as 1/4 tank just moving the car from a slight incline to flat ground (or vice versa)

 

[StealthSpeed3]

also your driving style could play a factor as well.

 

[FunK73]

i second that motion

 

[1Kris06]

and that the needle 'drops' slower for the first 1/2 tank. i can get up to 250 miles before i hit a 1/2 tank, and maybe only get 100 or so on the last 1/2.

 

[ClearCoatMiata]

im only getin 150 mile on a full tank

 

[mndsm]

Bad vac lines? The exhaust is bein' goofy? Fuel leak? Thrashed MAF?

 

[ClearCoatMiata]

now that i think of it we had the cat replaced at like 60k mile and customers were having problems with them clogging i wonder if its starting to clog again hmm