MichiganTL

After 92k of consistently getting 24-26 per tank, I'm getting 19-20? Had timing belt replaced @ 90k, but nothing else out of the norm. Very much a novice here, but thought you folks could give me some suggestions/ideas.

Thanks.

Tom Blasing

At 90k it could be quite a few things. My last car went about 60k before the O2 sensor started going out on it. When that thing starts to fail the computer puts the fuel injection into a "rich" mode that uses a lot more fuel than normal. The computer thinks the sensor is not warmed up yet and thus does not trim the fuel back to the ideal 14.7:1 air/fuel ratio that it should be.

One of those went for about $60-$80 on my old Talon.

axeman

Also, dont forget that you are starting to approach the recommeded interval for a tune-up...which is basically replacing spark plugs!
Have you noticed any other problems with the car? Also, how much did you have to pay for the timing belt and did you have it done at the dealer?

Thanks,
Axe

Vijay TL

Because you changed the timing belt, this would cause the car to idle and rev more. The timing belt has a lot to do with RPM of the engine. It may be idling too high and driving harder.

MichiganTL

1. (Tom) O2 Sensor - Seems I've had these go bad on every other car I've owned (325i, Volvo 850, Expedition, & Yukon XL)... but the 'check engine' light always came on. Any way to determine if this is the problem without blindly throwing $$ at replacing the part?

2. (Axeman) Other Problems? None. Still looks/feels like a relatively new ride. After 90k no rattles, no problems. Just replaced OEM Michelins with Conti-Extreme Contacts (slightly smaller tire) and they are awesome - after 5k wet/cornering performance is superior... at much less $$ (Oh, I've had Blizzaks in the winter, hence the prolonged tread life!). I'd say that the giddyup is not quite that of a new TL, but close enough (seems my loaner had a little more pop), but hey, 90k later to be expected. I think the timing belt was about $700 after tax & all - at the dealer. Spark plugs? Whatever it says in my manual under "normal conditions" is what I do - not much more than an oil change (synthetic) every 7500 miles. I did the belt early, but that's it.

My brother suggested a fuel additive / injector cleaner into the gas tank. I think I will see if that does anything first.

Tom Blasing

I believe there is a way to do it but I was never brave enough to go through with it. You have to measure the output voltage of the sensor when the engine is cold and compare that to when the engine is well warmed up. Too hot down there for me to work with a multimeter around there. If the voltage doesn't change (I don't know the limit specs for this car) or slow to change then it's either weak or gone South.