Fiirst, check the water level and make sure it has the proper anti-freeze mix. Always check your water level frequently. 2.9s are noted for cracking heads or blocks if they get too hot.. Second, it's cheap, just change the oil and filter, then make sure the trans, x-fer case, and both diffs have the right amount of gear oil. If yer feelin real friskie, change 'em. Fresh oil's always better...Cap, rotor, plugs, and wires and that's about as much as you can do for starters. Oh yeah...check your tire pressure. Pull the wheels off and inspect the pads and shoes, you'll wanna know when to expect to have to do a brake job..Check water level in the battery if it's not a maintenance free. Top off window washer fluid...fill the tank, get on the road...or off...