Hello, so I have a 2002 Jaguar X type 2.5 manual. I just got a few days ago and the guy said it needed an o2 sensor. When the engine warms up, when you press the throttle down, the car starts sputtering and jumping a little bit. It doesn't do it when the cruise is on or if I'm just keeping my speed steady, and it seems to do it worse in the higher gears. I'm completely new to owning a Jaguar. So if someone could point me in the right direction, that would be extremely helpful.

Thanks!

 

Is the check engine light on? Or any other lights lit on the dash? If so, please get the current codes read and post them here or do a search on here for them.

If no, possibly the fuel filter needs to be changed.

 

Jonalec, like Alfadude said, it is very possible you need to change the fuel filter. It would be a good idea to do it anyways just to know when it was last done as it should be done every 15K miles or so.

After that, based on the age of the car, I would be suspecting that you have a little bit of oil in the plug wells and this is causing a cylinder or two to misfire. This would also be a good time to do the spark plugs too if you are near 100K miles.

I would also get some MAF sensor cleaner and clean the MAF sensors. It could be as simple as that.

If you don't have a check engine light, I would say to first get into the car and turn the key to the RUN position. Verfiy that the check engine light comes on at this point (this is normal). If it doesn't, then someone has messed with the car. Once you have proven that the check engine light works, take the car out for a drive and if you can, find a long hill that you can drive up. Then starting at the bottom of the hill, do a long, hard acceleration up the hill to make the car stumble. Stay in the gas till the check engine light comes on. Then you can get the codes read to help pinpoint where your problem is. If the check engine light starts flashing, then ease off the gas such that the light stops flashing.

I figure this is a silly question, but I am going to ask it anyways: What grade of fuel are you putting in the car? This car requires premium fuel. You will find out that it prefers name brands too. Does it cost you a few extra dollars on each fill up. yes, but you can be chasing problems like this too if you go with the lower grades. Some people have had luck running the lower grades, but it is very hit and miss. It may also be a good idea to simply run a bottle of fuel injector cleaner through the car too. Unless you know the previous owner and what they did to the car, it is hard to say what someone may have done to the car that you now need to undo.