95XJman

I drive a 1997 Cherokee with 190,000 miles on it. I live at about 6500 feet and frequently drive upwards of 8000 feet.

Is there anything that someone would do to a 4.0 to make it happy driving around at elevation? I don't have any issues currently but when I drove a WRX I had it tuned to run in the thinner air and it made a huge improvement.

Just curious if there is anything that could or should be done to make it run as optimal as possible.

Thanks!

Bugout4x4

That's a very good technical question. One would think it would automatically compensate for this change but does it? Or does it do it well? I hope someone who knows more about these can share some more insight because I would be curious too.

Tbone289

Any vehicle with O2 sensors should automatically compensate. Could the fuel mapping better? I'm sure it could be tweaked for better performance, at any altitude. I'll leave it to the 4.0 experts to explain how that might be done, though...

4.3L XJ

I agree, should compensate for thinner air in the electronics. Used to live up that high and there were some tricks with a carb but all the new electronics took care of that

Cummins93

You could heat up your cps with a heat gun and tap it toward the passenger side about half of an inch. This advances base timing. I'm at 600 feet above sea level and don't experience knock even in the 95* summer days running 87. It didn't make a noticable difference at WOT but keeping 70mph cruising seems smoother/easier to maintain speed. Put a bolt into the strap before tapping it to keep it from becoming out of round.

Bugout4x4

The first thought that went through my head was "Kids... don't try this at home. Only trained professionals should "adjust" a CPS with a three pound sledge hammer." lol

jordan96xj

Did your WRX have a turbo? That's what will help produce more power at higher elevations. As for the Jeep, unless you really want to get deep into it, just keeping it well maintained is probably your most practical option. There is less oxygen at higher elevations, and the computer will adjust the fuel flow accordingly based on the products of combustion via the O2 sensor(s). Which ultimately means less power than when operating at lower elevations, unless air is compressed/jammed in artificially.