I have a 2002 Mustang gt that gets about 10mpg and i cant seem to figure it out, I have done a tune up, plugs wires and brakes. Didnt really help the mileage at all. I dont think i drive the car harder than anyone else who gets decent gas mileage so i dont think that is a problem. I dont know what i should try next.
Bad gas mileage
- Thread starter Raspo93
- Start date
Does the car have different gears? That would affect the odometer readings. what kind of driving do you do city/highway? Any codes or CEL? Do you smell gas around the car (leak)?
10mpg is pretty bad. In town, I generally get around 17-18mpg, and pure highway, 24-26mpg. It sounds
10mpg is pretty bad. In town, I generally get around 17-18mpg, and pure highway, 24-26mpg. It sounds
trinity_gt
10 Year Member
Which wires? The 02 has COP and no plug wires per se (at least not serviceable ones...)
wmburns
SN Certified Technician
How many miles?
Did the tune-up include new O2 sensors?
Did the tune-up include cleaning the MAF?
Are there any DTC codes?
Are there any exhaust or vacuum leaks?
+1 on the gear ratio. Very good point! If the odometer reads low, this will make the gas mileage appear worse than it really is.
+1 on the gas leak theory. It's a common problem for the gas tank filler neck grommet to dry and crack. It's easy to see that gas spilling out of the tank while driving will decrease mileage.
Did the tune-up include new O2 sensors?
Did the tune-up include cleaning the MAF?
Are there any DTC codes?
Are there any exhaust or vacuum leaks?
+1 on the gear ratio. Very good point! If the odometer reads low, this will make the gas mileage appear worse than it really is.
+1 on the gas leak theory. It's a common problem for the gas tank filler neck grommet to dry and crack. It's easy to see that gas spilling out of the tank while driving will decrease mileage.
Really need a full breakdown on the car. What mods? Has a tune been downloaded that could be off? Are you riding with the park brake on? Has any work been done to the transmission? If it's an automatic is the car shifting to overdrive? Do you drag race from one light to the other? Etc. Etc.
The car has 46,000 miles, all stock except for cut outs welded on after the cats on the h pipe. i cleaned the MAF a while ago randomly at a friends house because he had the spray for it. I didnt change the o2 sensors, i was thinking about getting a O/R x pipe to get rid of the cats if that could be a problem. The guy i bought it from said it was 100% stock when i bought it so as far as i know it has stock gears. There are no lights on the dash, its a manual. Also, when its full throttle it will smell like rotten eggs, idk if that would have something to do with it
wmburns
SN Certified Technician
Have the cats been gutted? If so, likely that is what the smell is coming from.
For all I know, it could be the cutouts. There is a reason exhaust is usually run all the way to the bumper.
Are you sure the check engine light actually works? It should come on during the lamp test.
Has the gas mileage always been bad?
Consider having the fuel injectors cleaned and flow tested. Injectorrx.com has done well by me.
Do you trust the PO? Seems likely that the car is stock but the tune is not.
Regardless, the best reasonable course of action is to start from a known good tune up.
03_TrueBlue_GT
Active Member
All of these are good questions but I have a few. Does the car have aftermarket rims on it like 18+? What kind of spark plugs are in the car? Whats your tire pressure at? how has the weather been where you are at? Is it really hot like hotter than normal? Are you using synthetic oil?
Thats all I can think of...
Thats all I can think of...
Stumbaugh
Member
Not having tailpipes on the car will not effect fuel mileage. I had dumps on mine for a long time and just recently put tailpipes on it (tired of the drone) and fuel mileage stayed the same.
Stumbaugh
Member
Stumbaugh
Member
This is true. I talked to my exhaust guy a minute ago and he said the same thing. He said that the cats are stopped up.
wmburns
SN Certified Technician
Almost double the gas mileage by installing a new catback exhaust system? Suggest documenting this as it would make a great ad. The exhaust makers will be all over you.
"Much to learn, you still have."
―Yoda to Dooku
03_TrueBlue_GT
Active Member
Haha true that, although I lost some mpgs after I installed my o/r x, but its probably the sound I love so I dont drive as conservatively as I used to lol...
Similar threads
