2002 Toyota Avalon Sudden loss of gas mileage

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?

2 Replies

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