Avalon mpg problem - Toyota Nation Forum : Toyota Car and Truck Forums

ColinM · 02-09-2004, 04:57 AM

1996 Avalon XLS with 102000 miles

I had a tune up at 99000 miles.
timing belt
water pump
NGK double platinum plugs
NGK wires
tensioners
fuel filter
PCV valve

Okay, here's the deal: My car sat for almost a year in a storgae unit. My dad would drive it every other weekend for 30 miles or so. It was also driven for a solid 2 week period just before I had the work done. The mpg was the same as before storage.

Before the tune up, I got 20-22 mpg with 70% freeway / 30% city driving. With 100% freeway, I would get 26-27 mpg. Post tune up I'm seeing 17-18 mpg in the same driving conditions (almost the exact same route to and from work, too). 100% freeway is now 28-29 mpg. That is awesome. It's an increase over pre tune up.

Any opinions on what the problem could be?

The mechanic checked the belt to see if it was a tooth off, but it wasn't. Everything was hooked up correctly. He had no idea what else the problem could be.

I buy regular unleaded gasoline at the same place every time. I moved around from place to place right after the tune up, thinking that something was in the fuel I was buying. I've stopped doing that.

Thoughts?

ColinM · 02-09-2004, 08:45 PM

bump

***Silver Streak*** · 02-09-2004, 08:53 PM

Did they adjust the timing? This happened to my friend's crappy Ford, and the only thing that they touched (got an oil change, brake tuneup) was the timing....

ColinM · 02-09-2004, 08:59 PM

I don't think the timing is adjustable except by moving the belt a tooth.

When my mechanic looked through the inspection door, he didn't mention that the timing was changed.

Plus, I don't think my 1 mpg increase from freeway only driving would be seen by a timing adjustment.

ReFLeX · 02-09-2004, 10:39 PM

how do u get 100% freeway??

ColinM · 02-10-2004, 05:04 AM

Quote:

Originally posted by ReFLeX
how do u get 100% freeway??

Fuel at the on ramp to the freeway. Drive 230 miles. Fuel at the off ramp to the freeway. Divide miles driven by the gallons used.

ColinM · 02-11-2004, 10:00 AM

bump

2000AVALON · 04-08-2005, 03:36 PM

bad o2 sensors cause crappy gas milage
check those.

airskeeter · 04-15-2005, 03:48 PM

Bad O2 sensors, regular gas might be a problem as well. Have you had the cat checked as well???
Have somebody put it on a computer to get the codes. I will bet that will tell you...

Jaggrey · 04-19-2005, 09:52 AM

that probably explains my problem. My CEL came on a few months ago and when I checked the codes it complained about the O2 sensor. Are the ones they sell at AutoZone for ~$70 ok?

2000AVALON · 04-19-2005, 09:57 AM

They should be fine. Make sure you get the direct repalcement oem ones not the universal ones where you have to wire them yourself.

http://www.oxygensensorwholesale.com...valon_xls.html

Jaggrey · 04-19-2005, 11:47 AM

Quote:

Originally Posted by 2000AVALON

They should be fine. Make sure you get the direct repalcement oem ones not the universal ones where you have to wire them yourself.

http://www.oxygensensorwholesale.com...valon_xls.html

cool.... that'll fit a 1998 avalon?

2000AVALON · 04-19-2005, 01:13 PM

heres the ones for your 1998

http://www.oxygensensorwholesale.com...98_avalon.html

Jaggrey · 04-19-2005, 01:34 PM

Quote:

Originally Posted by 2000AVALON

heres the ones for your 1998

http://www.oxygensensorwholesale.com...98_avalon.html

cool thanks man. I appreciate it!

Jaggrey · 05-23-2005, 07:14 PM

Ok I'm completely confused.

I just got the CEL read again since I'm finally gonna replace the sensors, and this is the code that came up:

P0135 - O2 Sensor Heater Circuit Malfunction - Bank 1, Sensor 1

From what I understand there are 3 sensors in the car; 2 before the cat and 1 after. Which sensor is this code referring to?