Causes for poor gas mileage?

[blind34_1]

Well I bought another car to add to my fleet, but it's getting a little less fuel economy than I expected. (Its a 93 celica GT)

I'm trying to think of all possible causes for bad gas mileage, here's what I have so far:

dirty air filter
clogged pcv valve
a lead foot


not a very good list, i know, thats why I'm asking for input. The last item there I'm working on, I'm just so used to putting foot to floor after driving that escort that its hard to change.

and also I've heard that a cold sir intake could help fuel efficiency by a small bit. True or no? Sounds like BS to me, more air, more fuel, you know?

[GT40FIED]

I'd add bad O2 sensors or possibly bad vacuum to the regulator. Man...I hate chasing down problems like that.

[pbateson]

Diesel engine?

[Kyle]

how big's the engine?

[AkimboStylee]

air filter
spark plugs
spark plug wires
dist. cap
dist. rotor

[GT40FIED]

Just remember...what won't kill you eats gas.:thumbsup:

[mylittlecivic]

man this 300lb kid was in my car along with a bunch of medium sized girls and the poor thing burned more gas:o

[blind34_1]

its a 2.2, and no paul, its not a diesel engine. However I was looking at some diesel vw's just for the efficiency. hell, half the time diesel fuel is cheaper than regular !

Yeah, good call on the o2 sensor. its got two, so double the chance for one to be bad.

and by bad vacuum to regulator, do you mean fuel pressure regulator?


and any comments on a cai helping fuel economy?

[ChrisCantSkate]

what mpg are you getting?

[GT40FIED]

Originally posted by blind34_1
and by bad vacuum to regulator, do you mean fuel pressure regulator?

Yeah. With a vacuum sensitive regulator, as engine rpms go up, vacuum goes down. As vacuum goes down, it opens up the regulator and allows more gas. If the vacuum line to the fuel pressure regulator cracks or leaks or whatever, less vacuum gets to the regulator and it thinks engine rpms have been increased and will add more fuel. A brilliant design, huh?

[blind34_1]

well i just filled up again, and i guess it isnt as bad as i thought. this last time i got 25.8 mpg. I guess it just seemed low, but its really not considering:

its a bigger engine than anything else I am comparing it to (the 1.9 in the escort, and the 1.6 in the civic)

the fuel meter is physically bigger (this would allow for a more precise meter movement, making me THINK that I'm burning more gas. in reality, its just more accurate.)

air filter is hella dirty

gas is damn expensive


I don't always keep good track of my mileage, i just get an average feeling of how well im doing, so i really shouldnt be bitching. It seemed out of whack, but i didnt consider everything.