Hello fellow Jaguarians,,,

So, my gas mileage just started sucking. I mean a considerable amount. I normally get in 20's mpg, but I'm not sure what it is now, but it is enough to make me jump on here. I would venture to say 12 mpg at best. I assume it is going to be a vacuum leak somewhere, so I was wondering the most common and/or frequent ones to check first. I'm on the case today while the weather is decent, so thanks in advance for the input. I recently changed the water pump, and I do not think that would influence anything, but I thought I would throw it out there just in case. You never know these days. Okay, I am about to "shine up my tool belt," "get my game face on," and "get ready for this hate part of our relationship." I am a self-doer because it is less-expensive, and mostly because I do not trust anyone else to do it...(trust issues maybe,lol) Either way, same result...

DatDude...

 

DatDude, just to ask a silly question, but do you use your e-brake recently (ie, just before things started tanking on you)? I have noticed that the e-brakes will tend to grab and be a big boat anchor to our cars and it will dramatically affect the gas mileage. The quick check is to apply the e-brake and as you are pulling the lever check to make sure that you are feeling resistance right off the bat, not being able to pull the handle up a ways and then feel the brakes offer some resistance. The other check I would make is to go for a drive and get the car up to say 50+ MPH for say 5 miles and then immediately pull over (try not to brake really hard). Are the rear wheels slightly warm or are they very warm? If they are slightly warm, then odds are it isn't your e-brake acting up. If they are really warm (especially a difference between the sides), then one of your rear calipers is binding up and dragging on you. Probably not a bad idea to also check the front wheels (expect the fronts to be slightly warmer than the rears, but not by much).

Since you don't mention a check engine light, I am assuming that it is off. If it is on, get the codes read and lets see what the car is saying. That may give us an idea of what is going on here.

 

Have you noticed if your water temp. is getting up to the normal range?

 

She runs absolutely fine with no issues at all other than poor gas mileage??

All service items up to scratch?
Just trying to build a better picture of whats been done and what hasn't?
Also you have nothing in your sig and haven't stated age and mileage?

Thanks

 

Hey fellows, my apology for the delayed response.

It has been a hectic week with a bunch of blah, blah, etc., etc.,

Therma, I have used the e-brake previously and I did check the tires after driving for a bit. The heat coming from the wheels appeared to be normal, though the passenger rear seemed a little warmer than the others, but not enough to lean me in that direction.

I did the test that you mentioned, and the e-brake seemed to be normal.

Tennscott, the water temperature is running at normal, though I did replace water-pumped recently.

JimC64, yes the car performs fine except for the gas mileage.. A few extra details for you all- Thermo, " before I replaced the water pump, the ABS and engine light were on and had been on for a while, but I was procrastinating about fixing.

After replacing the water-pump, oddly enough, both lights have gone off. I do think ICP is going a little whacko because all the gauges go off, and then come back on, like a "loose connection or something." I have read about weather change and low tires, etc., etc., and I assure that those are not the problems,,lol.

2002 Jag X-Type 3.0 160,000 mileage and I will update JimC64. At one time I was thinking about a faulty fuel hand because I put 10 dollars in gas and it give me a little over a half a tank of gas, and we all know that's a lie...

Thanks in advance.....

Again, I apologize for the delayed response.. Oh yea, I had it scanned at the local parts store, and it showed P0420 trouble code for the map sensor. I do not know if the code was new or old, so I will have it scanned again to double check...

DatDude

 

What does the trip computer say the mileage is???

 

Tony_H, I do not remember what that trip computer mileage is, or "if I am even sure of what you speaking of, the actual mileage is at 170,000. Is that what you mean or are you talking about something different? If different, just a little extra detail for me and I'll check it out..Thanks in advance...

 

If you press the button on the end of the turn signal stalk you will cycle through trip computer functions in the odometer window. One of them is fuel consumption.

 

Tony, It ended up being a faulty gauge. I do not know what caused it and haven't resolved, or even attempted to resolve it yet, because now i have transmission problems...smh..