CLEAN IT OUT!
Recommend that you use Auto-Rx (per directions; see website under Forum Sponsors) along with an inexpensive 10W-30 and filter. (And then every 25-30k).
KEEP IT CLEAN!
Also recommend that you use FUEL POWER to help clean up, and maintain fuel system/combustion chamber. (Website; as above.)
If you'll do a search on my member number in both "Additives" and in "Used Oil Analysis" you'll see the experience I've with both on our 2001 JEEP Cherokee (now at 77k).
Have used these products with excellent results (the FP pays for itself just in out-of-pocket fuel costs; and I've had [2] Jeep techs tell me that rarely have they seen such good numbers when checking over the fuel system).
As oil, I have used Mobil One 10W-30 since break-in, switched for 16k to Mobil One 0W-40 (see oil analysis), and am now using REDLINE 10W-30.
And, while the FL1-A size is the cross-reference, I'd suggest the better BALDWIN B2-HPG, the FLEETGUARD FL-3487 or the DONALDSON P1690781 (ck part numbers on both). These are "Extended-Life, Severe Service" with better flow and service life.
(Of course, if you are going to run an ordinary oil only 5-6k miles, then an WIX 51515 is a very good choice (same as the NAPA Gold).
You ought also to search Member #9 (Terry Dyson, of DYSON ANALYSIS) recommendation of these products, along with LUBE CONTROL. (Please understand that there are many excellent commentators here, I simply have used Terrys' services in the attempt to keep my motor as new -- not simply "ok" -- for better than 150k).
Do some searching. As Bror Jace indicated, this motor is well-represented around here.
Good luck.