demanufactured

I have an 1999 alero, and im getting horrible mileage. Ive gone through a half tank and gone 100km or 60miles. I just put a new O2 sensor on, and its not running too rich. When I first bought it we found some gas in the oil, but nothing seems to be leaking into there now. Any idea where this gas is going??? Thanks!

candra2

I recently noticed a similar problem with my 99 alero. I have calculated that I am getting approximately 15mpg. Can anyone give direction as to how to diagnose this problem?

demanufactured

candra...I have had this car checked every which way and all we can find is that there is a gas gauge problem.....the problem being that it doesnt work so good! The city milage sucks with this car but highway milage is really good. Go figure that. Guess we just gotta live with what we bought

crogers111

I'm experiencing the same mileage problem right now with my '99 2.4L (76,000miles). I'm used to getting 20-21 mpg city and am now getting approx 15mpg. (The fuel warning light used to come on at about 280 miles or so, and now comes on around 220 miles)


I changed the air filter and took the car to a GM dealer for service, where they identified and replaced a faulty coil pack. They also serviced the EFI. But the bad mileage is still there. (luckily I had an extended warranty type package and didn't have to pay for their guesswork). It is colder now but I didn't have this problem the previous 3 winters and it doesn't get that cold in No. Cal

I'm planning to take it back soon.

JTrujillo86

Was there any indication that you coil pack had went? Was there any stumbling of the engine or any SES light (Service Engine Soon)?

Jeremy

crogers111

No there was no indication that I saw (light or performance) that indicated a faulty coil pack. I only reported low fuel mileage. I had the alternator replaced at the same time....I had a battery light that would come on once at a certain RPM early in a drive, then go out. That problem is resolved but the low fuel mileage problem persists.