I noticed that on my last tank of gas I got only 200 miles...which is terrible. I did have my oil changed over the weekend and did notice that the oil level is over the maximum level (I normally change it myself, but since I'm away from home for an internship, I just had some local place change it).

I'm not sure if the excess amount of oil is causing the horrible gas mileage or if there's something else thats causing the problem. I have 77,350 miles on my car and I've been driving around pretty conservatively, shifting at around 2000-2500 rpm. I've also had some highway driving mixed in too, and I usually cruise around 80.

I was also thinking that a fouled spark plug might also be a culprit, but I'm not sure. Any input would be helpful. Thanks.

 

running your ac lately or maybe tire pressure is not right.

 

Sorry for not mentioning this before, but the previous tank I got a little over 300...

so this is a considerable drop in gas mileage. I hope its just the gas. The car drives fine as usual, no feeling of lost power. The tire pressure in the tires is fine, so I'm pretty stumped about this.

 

1) Check tire pressure (37 front and 34 back, don't go by owners manual which says 30).
2) Change air filter if needed (go with only OEM).
3) Change PCV valve if needed (you could clean it with carb cleaner if the valve is not stuck and hear tick-tick if you shake it).
4) If you are on original coils and plugs (go with 2K1 coils) and had extra money, I would recommended changing it (I gained 3 to 4 MPG once I changed the coil/plug set, but I changed them only when I got a P1320 SES code). This could be an expensive deal close to ~$400, call DaveB @ 1-888-254-6060.

This is what I could think off (based on my experience to raise MPG) but there are a lot of experts out here who can suggest other items to check.

 

37 PSI in the front? I'm not saying you're wrong, but I'm running 32 PSI, anything above that and I think the ride becomes to harsh. This may be different in the 5th gen vs the 5.5th gen though.

 

My ride is quite fine (well it is in the mind of the driver) except that it is harsh while going over the threadles. I used to run 32-34 sometime back and had my sidewalls started to crack, with a H rated tire. I rotated it every 6 months and got the 40K out of those tires. I have replaced my tires since then I have stuck to the above formula and my sidewalls are better.

 

Check your O2 sensors.....before my SES came on, my mileage went in the toilet.....then it finally coded.....there are three of them....if it is a O2 sensor be sure of the right one........otherwise, you could have gotten some bad gas, if it just started on this tank.....

 

hmm 200 is what i usually get with city driving... perhaps i have a problem too. i only get 300- 350 with pure highway miles.

 

There is something wrong with your car or else you're driving pretty darn fast.
I get 500 to 550 straight highway driving on my 4th Gen and I'd pull my hair out if I only got 300 -350 pure highway. I can get 350 on a slow commute.

 

My god, I've never seen over 220 in my max. It must be because I drive too fast. I am split about 50/50 driving with an autotragic. On the highway, I usually cruise between 80 and 90 mph. Wish I had a 6sp.

 

Might be caused by a failing MAF. I have 113K miles on my original O2 sensors and everything else is original but the MAF and plugs and I just got 546 miles on a tank full this weekend. I monitor my Air fuel ratio all the time, I got a wideband 02 sensor hooked up so I know what up.

 

as far as i know everyone in NY area gets the same bad mileage.

 

I got 396 miles on 1 tank this week then I got nervous and got gas anyway.
Filled up with 15.5 gallons!! I had 2.5 gallons left maybe.

This with 110K miles on the car, same stock spark plugs and coils, super dirty K&N filter and in need of an oil change. :-)

 

I'm not really noticing a power loss though, so could it still be the MAF?

Also, I'm gonna run another tank of gas just to make sure that it wasn't bad gas.