I have a x-type 3.0 needs oxygen sensor fuel consumption is 17 mpg is this normal easy driving

 

I've moved your question from General Tech Help to X-Type forum. Members here with the same model will be able to help.

Graham

 

Dave: Welcome to the Jag Forum. My 2002 2.5L X-Type Sport with ~125 kmiles gets ~28-30 miles per gallon on mostly highway driving, and in the low 20's around town. Your 3.0L should get close to that, so I'd have to agree that 17 miles per gallon indicates a problem.

How have you decided the problem is an oxygen sensor? Is your check engine light (CEL) turned on, and you've checked the car's computer for error codes?

If 'yes', what is the error code? If 'no', this is a good place to start. Many auto part stores will check your error codes for free, or a mechanic can do it.

Our Jags have 4 oxygen sensors. Your Jag's computer error code will tell you which oxygen sensor is bad, or if a different problem is causing the poor mileage.

 

Dave, before you start diving too far into this, do the obvious checks first. Our cars normally are suffering from a vacuum leak when the mileage really starts tanking. So, check the PCV hose for a crack on the underside, the IMT o-rings for a leak there, and then finally the vacuum line running between the top of the intake and the brake booster (the football in the center, aka check valve, is normally the big offender as it will dry out and the plastic will start to crack and/or being very powdery).

After that, disconnect your battery and reset the computer. You will need to reprogram your windows, but that takes all of 2 minutes to do following the reconnecting of the battery. I have noticed that our cars will develop a certain memory to it and it will sometimes affect the mileage, especially if you have 2 people driving the car that have completely different driving styles.

The final thing that I would tell you to do is to clean the MAF sensor. If this gets dirty, it can create havoc. Probably not a bad idea to add a bottle of fuel injector cleaner and to also switch to a different name brand of gas for that one tank (each manufacturer uses a different detergent blend and if you use the same brand over and over, it can still build up some amount of gum since the gum that develops is not covered by the detergent package of your normal gas station, the different station will have a different detergent blend and it will normally get rid of any build up that has occurred). See what you have at that point. But, like was mentioned by dwclapp, do you have codes and if so, what are they? That may help us narrow down what is really going on.