kinda noobish driving impression question...

So I've been dealing with Jeeps going on25 years, give or take a few decades. I just got this 01 XJ and have a question that seems a little stupid even to ask but I'm curious what the general consensus is. This is a bone stock, unmolested 2WD sport. As I have been slowly working my way under the hood and found myself working the throttle by hand I felt like the motor was a good deal... sluggish? Its a 4.0 with about 150k on the ticker. I have yet to pull plugs or any kind of tune up ritual yet but it still seems like its not as spunky as most of the other 4.0s I've owned over the years. So not counting the age/mileage etc... In basic form has anyone noticed the "newer" 4.0s to lack oomph?
And sorry for dropping this in the S&P thread... wasn't sure where it would apply.

My '01 was Much slower than my '98. Both automatic 4wd same gears and tires. Never found out why because the head cracked before i could investigate. That said, on my '98 it always had a spark knock on light loads. I had a 3M injector cleaning pressurized bottle run through it and for the next three tanks of gas i ran a bottle of Amsoil injector cleaner in it. The spark knock was gone and the power improved. I would do that first.

I have a 2001, 2000 (basically the same) and a 1998.

I never really noticed much difference between them.

Do a tune up, change the oils, etc. and see where that leads.

2¢

Thanks for the input folks. I fully plan on doing a complete tuneup and service to this thing, hopefully this week. I have some gaskets and seals that I know need replacing already (oil filter adapter,valve cover, and tranny output) so following that it will get plugs and fresh oil etc.
Do any of you have a link to a good thread to read about the head cracking issue? Not so much the replacement but more the symptoms, and potential temp fixes...if that makes sense. I know if its cracked it will get replaced but I'm curious as to how people have discovered thiers was bad and what it did to the motor. I've read several on here and on Cherokee forums but they all mostly have just started with "my head was cracked so I..." and then they go into swapping the head. Guess I'm looking more for the beginer part of diagnosing the crack.?.

You are right. My 2000 felt sluggish compared to a 93 ZJ (AW4) I had at the time and a 91 XJ I had previously. Modify the air box or go with CAI and it will feel a bunch peppier. The airbox has a hole in the front that opens into a piece of metal, not good for flow. However, most of the power loss is probably due to emissions programming and staying in closed loop much longer than previous years.