Thread: CEL and terrible gas mileage

Alright, so I've been at school now for the past 3 weeks, and I've noticed about a 5mpg decrease over that span of time (22 to 17).... further, last night my service engine soon light came on. I believe these 2 issues are related.... maybe oxygen sensor or something emissions related?

Does anyone have a scanner tool in Whitewater, WI area - or not far from? I'd rather do that than pay $80 for a diagnose and then have to pay another god knows what on top of that..... I'm a poor college student! haha.

Any suggestions/help would be great. Thanks.

Well a faulty O2 sensor (pre-cat anyway) would certainly explain a loss in mileage. You can take the car to Autozone and they will hook up a code reader to it for free and print out what you have.

thanks scotty, I'll have to take it over there, pull the code, and then figure out if its the O2 sensor.... (that's what I would guess)

Is your car getting up to temp? If not it could be a bad thermostat.

No, I think my thermostat is fine - its a 180 degree that I changed back in February. I think I can smell a gassy smell while I'm at stop lights.... I think its the O2 but I'll take it to autozone this weekend to make sure. Thanks.

Be sure to let us know how it all turns out and what you find out.

I went to Autozone today and they pulled the code: p0102

I guess it is for the MAF sensor, Throttle body, or Vaccum lines?

Anyone have this code, or could give me some insight on how to diagnose it? Thanks.

P0102 - Mass air flow circuit low input

New MAF.

Check the cheap simple things first.

Make sure your air filter is clean.

The intake duct is properly attached and not collapsed (not likely on a stock duct).

Nothing has gotten in and stuck to the TB screen

And mainly, use some sensor safe aerosol cleaner that leaves no residue and clean the MAF. Be careful when spraying the sensor wires that you dont damage them buy sprying too close or to directly.

MAF comes off with a T20 security torx bit.IIRC

Originally Posted by IndeedSS

Check the cheap simple things first.

Also, try cleaning it first. Some MAF cleaner, availble at most stores, remove your air filter, and spray it on the MAF. Let it dry and see how it does. Can't hurt....

The light has mysteriously turned off for the past few days.... so I'm not going to mess with it. However, next time it turns on I will definitley take it apart and give it a good cleaning before replacing it.

Thanks for the input!

I would double check your fuel economy......just in case.

Originally Posted by GreenNirvana101

The light has mysteriously turned off for the past few days.... so I'm not going to mess with it. However, next time it turns on I will definitley take it apart and give it a good cleaning before replacing it.

Thanks for the input!

Just because the light went away doesn't mean it is fixed. Actually, it is probably not. Do what you want, but it is probably cheap to put the money into parts and fix it correctly than drive around with crappy gas mileage.

well, i spoke too soon, and the light is back on again! looks like i'll have a job ahead of me this weekend.

I'll just start by taking it apart and cleaning it out - I really hope that fixes it! Otherwise, anyone want to sell a used MAF?

MAF no, but TB with MAF from a 97....sure. if you want it you can have it..lol

how far away are you now since your in school?

Jacob - you gots a PM! haha

pm'd ya back!