Gass milage went to hell

[camaro_speedemon]

I would say the past 2 months, by city milage has gone from 21-22 to about 18-19. Last time I was on the highway, I only got 23MPG! I last road trip I went on, I didn't see under 27, and that half hauling at 90MPH and the other half hauling through mountain switchbacks.

I haven't changed my driving style. My fuel filter is fairly new, my tire pressure is right, my plugs and wires only have about 10-15k on them. I cleaned my air filter two weeks ago, I thought that might have been the problem because they were black, oops [img]redface.gif[/img] . I'm about to go buy some fuel system cleaner, maybe that will help? I can't think of anything else that would make my milage go to sh*t, anyone have any more suggestions?

[95Batmobile]

only other thing I can think of is thermostat or O2 sensor...

[PewterBird]

Are you carring any extra weight.?

I have a habit of letting books and cloths and stuff pile up in my trunk durin the semester. That stuff adds up and cost you money when it comes to MPG.

[Ian]

ok, i got a 96 m5 camaro, and i drove very conservateivly on the way back from college one day.

i got 18mpg.

i just got my car like a month ago. how can i tell if its ever had a tuneup before?

[Dominic]

Its the fuel, my fuel economy went way down recently due to the fuel. I started running 89 for grins and it went up, try a tank.

[navyblue2000]

<blockquote>quote:</font><hr>Originally posted by Dominic:
Its the fuel, my fuel economy went way down recently due to the fuel. I started running 89 for grins and it went up, try a tank.<hr></blockquote>

i get a combined 26-27 city/highway, running 89. running 87 i got 28 ALL highway. get 33 all highway with 89.

[ellik]

i was only getting 16-18 city running 87 and 26 or so highway. now i only run 93 and always break 30 on highway and running 22 city.

[MustangEater8251]

how many miles sure its not your o2s?

aren't black plugs caused by runnign rich? If o2s are fudged, they will send a wrong signal and cause you to run rich, and kill your gas mileage.

Hee my car once got 12 mpg on the highway, and that was bach when I still had 3.23s [img]smile.gif[/img]

New o2 doubled it for me. I changed them jsut before 100k

If you come up back to Orlando I think I still have the o2 sensor socket laying around. But then again I think autozone will lend one to you for free.

[ September 22, 2003: Message edited by: MustangEater8251 ]</p>

[camaro_speedemon]

<blockquote>quote:</font><hr>Originally posted by Dominic:
Its the fuel, my fuel economy went way down recently due to the fuel. I started running 89 for grins and it went up, try a tank.<hr></blockquote>

I tried that just for ****s and grins. I was thinking about the O2 sensor, how do know it's going bad? BTW Eric, my air filter was black, not my plugs.

And I did a little experiment a few months back on what gets better milage. I ran 87 for a few weeks, then 89, and then 93. For some reason, my car gets better milage on 87.