4.0 L spark knock

'91 and later wranglers do not have a knock sensor. Knock comes about from running too lean, too advanced, or too hot, or not enough octane. Dino's adjustable map sensor:

Thanks all for the feedback.dw

I have an '03 with an I6 and I get it too (though it's not at all severe). Not all the time, so I just write it off to "bad" gas.... It started at about 20K miles and I now have 55K miles. I get my gas at the same place usually, so I'm not sure if it is vendor specific. Do you run the hi-octane because of the supercharger? If not, why? Higher octane gas is less volitile than regular- it takes more heat to "explode"- and I've been advised NOT to run it in the Jeep.

Dalewhite did pass the time by typing:

For me it's usually bad gas and a bottle of the NOS brand gas drier does wonders. There are others out there, just make sure they are safe for the O2 sensor. A local 7-11 gave the ZJ a real classic "blown head gasket" white cloud one time.

Did they give you a heat range cooler spark plug? You should probably be running at least one heat range cooler. For the I6 that's an RC9YC4 or Autolite 3924. Hot plugs can be a source of preignition problems.

There are various sensors that can also do this but you would have lots more problems than just a little spark knock and I don't believe your 00 has an external fuel filter to mess with, think yours is in the tank.

Good luck. Hope you find the problem.

Isn't a butterfly valve part of a carburator? Don't know engines well enough to know for sure....

Dale: I would like to here more about your Avenger Supercharger. I have a 2k tj and plan on a supercharger. I am increasing cooling (griffin radiator) - if quadrtec will ever send it. Then header and exhaust. Then the supercharger. Why did your pick Avenger? Did you install yourself? Any problems? What's it like to drive? Thanks - Allen

been there bill. they only had the best to say about their product. i'm sure it was a balanced view.

supercharger.