Crappy gas mileage

Jim Meyer did pass the time by typing:

How old is your O2 sensor? They can drift off without throwing codes and then the engine runs rich and milage goes to pot.

The other culprit is leak-down on the injectors. Measure the fuel rail pressure, it should stay steady for more than 20min, if it leaks down fast it could be the pressure regulator, check valve, or leaky injector. Both a leaking check valve and pressure regulator will cause poor performance and real lousy starts with lots of cranking. A dripping injector just makes that cyl run rich and sucks gas.

get a prius

herman did pass the time by typing:

Now that's just silly, a prius with 35" MT/R tires probably couldn't even move.

I got 4.5 MPG (nope, not a typo) on Thursday in my 99 TJ! 92 miles and it was going on E.

Freakin' catalytic converters..

Eric

Something hugely wrong there. I have a 4LTR Auto XJ 1994 vintage and

39k miles on the clock. As I've only had it a few weeks I've been very careful to log MPG. On last refill, it calculated out as 19mpg (UK Gallons) which isn't as bad as I thought it was going to be. With a full caravan in tow, all the family and gear, I got 15mpg on a two hundred mile round trip. Also, not as bad as I expected.

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I've been keep track of my mileage for a couple months now and the worst I've gotten was about 15mpg (based on liter to gallon calculation).

The best I've gotten is 21.5mpg. I wasn't doing so hot with mileage until, Mike Romain, I think described how he doesn't use his OD (5th) gear at regular highway speeds. I only use OD when I'm doing more than 120kph.

Like it's been said, don't drive it like a sports car....

I told the stealership to check it out... .I sure hope I didn't trash anything. I had no choice but to wait until now to get it fixed. The problem didn't start until I was at OTS, then I had to get home somehow... really no problem until Thursday. Then I took it in. Any idea how to check the valves??

By the way, apparently the nearest cat at ANY dealer is in Arizona (I'm in San Antonio). What the heck is that about? Dealers don't stock them???

Eric

Not really an unusual situation, aside from being a low volume repalcement item (modern cats are very robust and don't fail with any regularity) cats are really expensive for a dealer to keep in stock.

What usually causes a cat to fail is outside influence (a rock or other road hazard). Most modern systems go into some form of limp home mode that will prevent the cat from loading up with fuel and overheating. Unless it's clear that it failed from being struck from the outside, it would be sensible to have a knowledeable tech check this thing out with proper diagnostiocs eqpt before you replace the cat.

where is the cat? part of the exhuast system isn't it? How would it load up with fuel?

couldn't you just pop it off to get a better "limp-home" mileage?? Cops may get nasty about it...but if you're burning a LOT of fuel anyhow, I doubt you are within emissions specs!

SB did pass the time by typing:

Leaking injector, failed sparkplug/wire, cracked exhaust manifold, or drifting O2 sensor.

The cat is located just before the muffler. It could be removed if the clamps haven't rusted closed and you have a air chisel or hotwrench.

That's what they are SUPPOSED to be doing. There are a couple of problems with that, though:

1. I didn't buy it at this dealership. So what is their incentive to do "above and beyond?"(although I've purchased two cars from them about 3-5 years ago)
2. It isn't under warranty anymore. The cat is due to the 7 year emissions warranty, but that's it.

Also, I know there wasn't any damage to the cat from outside hazards. I looked it over myself. Besides, it's very well protected by the stock skid plate. Wow, that seems kind of strange to say.. "very well protected by a stock...". ;-)

Eric