Thread: Poor gas mileage

remove and clean, not sure on what to use tho.

change them, i say every 40-50k.

i drive 85% city and get around 16-19 depending on stoplights and stoplight road rage and normal puttering around. 30 ish freeway.

Originally Posted by jackdup

Thanks for the replies.

Is there any easy way to test the O2 sensor or do you need a scan tool?

Also as far as the TB can it be cleaned with a spray type carb cleaner or does it have to be removed and cleaned?

Plug wires "appear" good. Was planning on changing the plugs anyway but with about 60,000 miles on the car didn't think they would be bad enough to reduce the mileage that much.

Do you know what one can expect for mileage in the city? I know what the EPA ratings are but they are often not what the average driver gets for mileage?

Thanks

Q#1 Well, you can test the output voltage on the O2 sensor. But that isn’t 100% accurate, also consider the fact it could “work” but be slow responding. I’d get the car scanned before worrying about the O2 sensor ATM. The sensor “should” last a least a 100k, but then again just had one go bad on a friend. It was on a Toyota with only 20k on it, I thought Toyotas never broke.

Q#2 You can clean it with regular carb cleaner. You don’t need to remove the TB. In fact, I recommend that you don’t. Remove the intake tube, and unplug the TB cable. Use your finger to open up throttle plate. Clean the back side of the plate and the TB walls. Then put it back together. Easy cheesy. I clean mine once a year, so far zero problems. Let me just add that this is good maintenance to do, however a gummed up TB shouldn’t effect your mpg. The normal symptoms are starting and idling issues.

Q#3 Your plugs and wires should be just fine. However, I would pull a couple plugs just to check them out. Even though the plugs “should” last for 100k, you may want to consider replacing them. The difference in time it takes to check them vs. replacing them is nearly the same.

Q#4 IMHO most ppl with un-modded cars get slightly higher than EPA mileage. I personally get 2 mpg higher than EPA on average. I track my mpg like a hawk, and the most significant factor in my mileage is my average speed. If your one of those ppl who waits in drive through lines every day at banks and fast food places your mpg will suffer. If you city drive all the time in a wise fashion you should be able to get at least 16 mpg. If you give me your DIC avg speed, I’ll tell you what your mpg should be.

These are the big tune-ups for mpg:
1) new O2 sensor
2) new spark plugs
3) MAF cleaning
4) proper tire pressure

If I were you I’d first clean my MAF sensor, only because your car is so new. Then I would have the car scanned.

Get back to us.

Originally Posted by jackdup

As far as avg speed, I assume that is reset when you reset the Trip mileage, which I did after the last fuel-up so will have to wait a few days so it is a little more representative.

Ummm, nope. As far as I know the AVG speed doesn’t reset with any other function. You need to reset it independently of the trip counter. I reset my avg speed every fill up, most people never mention this function in mpg discussions, but that one number can deliver quite a bit of insight on mpg.

Originally Posted by jackdup

Last time I checked it it was 20.8 km/h but again will check it tomorrow

I’m nearly speechless, 20.8 km/hr? Really? That is a crazy low average speed, just for a comparison my average speed is about 61 km/hr. I didn’t make my number up it is based off 10k+ miles of driving data. Assuming you gave a good number I have a mixed bag of news for you. The good news is your car doesn’t have a problem; it is actually getting the gas mileage it should. I personally had to extrapolate my data out significantly to compare with such a low average to be honest. I rarely average less than about 54 km/hr. I’ll I can say is you must travel in constant bump to bump traffic, or you let your engine idle way too much. As you mentioned get back with some more data, we’ll figure this out.