Gas Mileage Problems


New Member
Jul 21, 2005
Atlanta, GA
This has been getting worse as time goes on back in late July I changed out the plugs and wires thinking I would get better gas mileage. Wrong. It has progressively gotten worse from like 320 miles to a tank to like 280 and now it flucuates from 220-260 since I got flowmaster mufflers installed. Any suggestions on what to do. It's really starting to get increasingly annoying considering gas is about to go up again.
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What is this gas "mileage" thing of which you speak? Is that a gasoline additive that makes the car go faster? :scratch:

Seriously though a lot of things affect this including the fact that cars get worse mileage in cold weather.

How many miles on your fuel filter?
I don't think the fuel filter has ever been changed. It's got 95000 miles on it. All I did was change the spark plugs and plug wires then it got like 40 to 50 miles less a tank. Then I got flows and now I get like another 30 less.
Change the fuel filter asap. You sure you gapped the plugs correctly? If you are reading this and thinking "They come pre-gapped!" .. they still need to be checked anyway.
#1 - Change the fuel filter!!!!

#2 - My fuel mileage has always dropped for a while after I changed a part of my exhaust. Not because of the exhaust, mind you, but because I didnt shift as early as I used to. I just wanted to hear the sound of the exhaust. When I did the cat-back, I found myself turning down the radio at stoplight just so I could get on it. After a month or so, that got old, but then again after I did the LTs and the O/R X I did the same thing. Are you doing this? That will cut an ass load out of your MPG, I dropped from 280 miles on a tank to almost 220, but after I would quit, right back up to 280.

Just my .02 tho......
I'd say give it some time. I think mine dropped too when I first put in Borlas. Also, check your tire pressure. Make sure you're not running on 20lbs. or something.

Edit: Or maybe you were real lean back then where you were getting 320. You had a CAI to get the air in but no exhaust mod. Only time I (5speed 04 gt) get above 300 on a tank is on a road trip. Generally, I am around 260-280 per tank. Just got a tune, so I'm going to be checking again.