So, i've had a 99 cherokee, 4.0, 4x4, 5-speed for about 2 1/2 years. And i've noticed that in the summer time, the motor is fairly sluggish on hotter days (90+ degrees). In the winter time, motor is mad with power, and has a quick response. Not a huge problem, but i want to do something about it if possible. I did a tune-up when i first got it, new plugs, wires, and distributor cap, new K&N air filter in the stock intake box, put in 784 injectors. Runs great and runs strong when its cool, just sluggish on hot days. Been considering putting in a cold-air intake. Anyone noticed a difference with a CAI? Or know any other tricks to help that issue?

TIA

 

Hot air is less dense and produces less power. Also, the oil companies screw with the fuel blend every summer.

Beware of some CAIs as they actually pull hotter air from under the hood than the stock airbox does.

 

"cowl intake", either home-brew or made by a company like Spectre, is the way to go. Or a proper snorkel or course. There is no other reliable way to get cold air in An XJ.

Also look into the IAT relocation mod.

Coolig system up to date? Actually noticing such a huge drop of power one doesn't hear about that often.

 

Cooling system is up to date. Fresh coolant and no leaks.

 

I guess a cowl intake may be in my future