2002 Toyota Avalon Sudden loss of gas mileage

Tiny
EROM43
  • MEMBER
  • 2002 TOYOTA AVALON
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 130,000 MILES
My 2002 Avalon XLS with 130K has had a sudden loss gas milage. I used to average about 27mpg on the interstate. Now I am getting only 22-25mpg. Inconsistantly. Around town has dropped from low 20's to high teens. It started about a month ago during a long trip up north. A couple of weeks ago we had more serious problems with stalling, erratic shifting, unable to start plus the milage problem. Spent $800 on analysis that ended up with codes showing IAC module needed replacement. Car runs much better, but milage problem still the same. Only major work was fluid flushes and induction cleaning, brake job and timing belt replacement one year ago. Tire inflation good and there are no other usage changes. Tried some Lucas a few days ago, but no significant change yet. Only other symptom is possible slightly louder engine noise. Getting ready for another long trip, and don't feel good about it. Planning on taking it back to dealer next week. Any suggestions?
Saturday, September 11th, 2010 AT 12:15 PM

2 Replies

Tiny
DSPLC
  • MECHANIC
  • 220 POSTS
Proper tune up

1. New spark plugs ( single tip - gap to .044")
2. Spark plug wires (not necessary but if you have not changed it yet since you bought the car, maybe it is time to change it)
3. New air cleaner (every 15,000 miles)
4. Change oil every 3000 miles ( May I suggest 10 W40 weight oil since you have over 100,000 miles on it, but it is up to you)
5. Clean/replace pcv valve ($10)
6. Add fuel injector cleaner additive to gas when you fill it up. Once, Every 5000 miles.

Regarding the spark plugs, choose the single tip Irridium or platinum spark plug. (NGK my preferred brand, NOT Bosch). I have tried the 2 tips and 4 tips, they run a little better but consumes more gas per mileage based from my own car's experience.

Single tip is the top spark plug in the picture


https://www.2carpros.com/forum/automotive_pictures/89255_spark_plugs_2.jpg



This is the only things I know but other mechanics might help you further
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Wednesday, September 15th, 2010 AT 12:26 PM
Tiny
DSPLC
  • MECHANIC
  • 220 POSTS
I forgot to say that correct tire pressure makes a big difference in miles per gallon of gas. Under pressure consumes more gas. Correct tire pressure is written on the driver's side door usually 30 to 32 psi of air.
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Wednesday, September 15th, 2010 AT 11:36 PM

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