Valve Tap 1997 4.0 Jeep Cherokee

[possum]

Had a valve tap. Ran a quart of Marvel mystery oil in it. Did not go away. Replaced lifters. Cam looked good. Still have a valve tap.

[carnuck]

I'd put CD2 engine detergent in. If that doesn't cure it, then it's more likely piston slap.

[volaredon]

I have the same thing in my 01. comes and goes, as it has since I got it at 94K miles, now has 167K on it. I've had noises that I've "Sworn" were lifter noises but turned out to be exhaust over the years. My wife drives the '01 daily. the noise has never gotten worse the whole time we have had it, when it's there it's the same volume and intensity as it always has been, I've kept a close ear on it ready to tear into something top solve the noise. but with us having put 73K on it in 4-1/2 years, and it has not worsened over that time or mileage, and it continues to be dependable as it ever was, I've quit worrying about it!

[Bounty__Hunter]

First thing would be to rule out a cracked header, most common tapping noise on the 4.0L engine. Then change the oil and replace a qt of the oil with a qt of ATF. Any lifter noise should be reduced or disappear.