ron45

I've mentioned before I was never much of a car guy in high school or after. So I was surprised to see some utube vids on fuel injector mods for XJ's. It's my understanding that the XJ classification is from 87 to ... I forget but maybe 99, is my 4.O engine fuel injected?

If that's the case are there inexpensive mods to improve gas mileage? Mine seems ok in the power dept. But I'm not crazy about the mileage I get.

While we are here, I try to stay in the 65 mph area on hiway driving but I notice the speed kreeps up to 70 or 75 occasionally. I always back off when that happens. Would driving at these speeds for long periods [1.5 hrs] shorten the life of the motor?

Thanks for your time.

Ron

mschi772

2.9 million XJ's were made from 84 to 01. They have had fuel injection since 86. Yes, yours is fuel injected.

There are about a bazillion threads asking this very question. Google. I've done way more than most people would with MPG in mind, and I've never exceeded 23 MPG on the highway in the best of conditions. My average MPG is 17-18 MPG. Make sure you're calculating MPG correctly (so many people do it wrong) otherwise any comparisons you make will be meaningless. I bought a Chevy Metro to commute with for a couple grand. Just a couple years and it paid for itself in fuel savings compared to my XJ and is still going strong. 40 MPG highway.

The best thing you can do is to keep everything well-maintained and go easy on the skinny pedal. People hate hearing this, but slow down. Drag increases EXPONENTIALLY with speed, and when you start getting into 60-70 mph territory with the enormous drag coefficent of the XJ, drag really starts to pile up. Since you have an 87, make this your bible--Cruiser's Mostly Renix Tips


Haha, no.

cruiser54

Pay attention to all of this^^^^.

Install a vacuum gauge in your line of sight and pay attention to it.

BlueRidgeMark

Not even a tiny little bit, Ron. Drive it cross country that way! No problem.



Oh, yes he has, Ron! He definitely has! He's kind of The King Of MPG around here. He's got a very long running thread on that very topic. Tons of information. Some of it's even useful!



I haven't done anything special to mine for MPG. Nothing. I've never exceeded 23 MPG on the highway in the best of conditions. My average MPG is 17-18 MPG.

So, there you go.

ron45

That's good news on the motor longevity, Kinda bummed about the milage. I should have done better research. Been driving Subaru's for about 15 years and got spoiled I guess. They were'nt spectacular but 30 is not bad. Thanks for all the great links. You guys are the bee's kneez.

Ron