Planning a "mayor" tune-up

[titodj]

Originally Posted by andrewwynn

My biggest mpg change was plugs. I got 7-10% better mpg when I replaced plugs. Still have suck mpg compared to wife's identical car (I get 20-21 she gets 23-24).

I think a lot has to do with driving style.
Also, I've noticed that clean injectors make a huge difference too.

[andrewwynn]

I'm comparing when I drive to when I drive. If I drive my wife's car with cruise at 75 I get 23-24mpg. Do the same with mine I get 20-21.

[Fifty150hs]

Originally Posted by andrewwynn

My biggest mpg change was plugs. I got 7-10% better mpg when I replaced plugs. Still have suck mpg compared to wife's identical car (I get 20-21 she gets 23-24).

I've changed plugs a couple of times. I tried single electrode plugs - mileage went down. Put quad conductor plugs back in and mileage went back up, but has started to come back down. I doubt the O2 sensors have ever been changed and I have 217,000 miles on the clock. Time for precat and postcat O2 sensor change or just precat?

[Drevco]

Originally Posted by Fifty150hs

What should those 02 readings be? I have 217,000 miles on my sensors and mileage has recently begun to drop.

I second Andrewwyn on this.
Bentley Manual dixit: O2 to change them to 160.000km. Don’t wait for errors.
An air filter should last xxxkm but if you drove thru some dusty roads you wouldn’t wait for the kms.
The improvement in mpg (or L/Km) is substantial. {Like a new battery}.
O2 sensors beyond kms are very sensitive to impurities also. I changed the 4 of them at 200.000km and everything improved: smoothness, reaction in acceleration, and autonomy.
If working with on steering lines the reservoir made by ZF was $27, it has a filter at the bottom that can’t be replaced.