Going to dealer to buy parts for tune up tomorrow

I'm heading to the Jeep dealer tomorrow to get a few things for a tune up. I have a '96 4.0 AW4 XJ w/ 66k and I'm getting 12MPG.

On the list so far:

Spark plugs
Wires
Dist. Cap
Rotor

I have a new AF and fuel filter already in. Anything else I'm missing? Would it be worth my while to pick up a can of GM top end cleaner? Should I run this before I change my plugs?

I am thinking of running a bottle of Lucus injector cleaner before I change the plugs. Would it be a good idea to change the fuel filter again at this time? I changed it about 1500 miles ago.

I'd do the cleaning thing before changing plugs and such. Top engine cleaner, dump some chevron techron in there, clean the throttle body down and then do the plugs, wires, cap and rotor. Check out the Mopar high performance wires, they are a few dollars cheaper then the mopar OEM ones... I think for your year you can get a HP cap and rotor too... don't forget to add the dielectric grease to your list too....
If the milage still bites it's time for a new O2 sensor I'm thinking...they seem to have the biggest effect on milage..

Does my XJ have one or two O2 sensors? I think some of the years are different. Where is it located, and is it tricky to replace? How much would I be looking at?

Are there any actual gains from the "high performance" wires/cap/rotor?

Bump for answers. I might be replacing my O2 soon.

They started the double O2 sensor thing with OBD-II, so you should have two (one in the exhaust manifold, one right after the catalytic converter.)

Check your new ignition cap and rotor and make sure the terminals are brass - the aluminum terminals are barely fit for the scrap heap. If you can't get them OEM, you can get them if you get Borg-Warner parts - they're what I use. I'd also go with Autolite Platinum plugs - AP3924 should be about right.

You can check your O2 sensor with an ohmmeter - I just don't have the specs handy at the moment...

I really don't bother with dealer/OEMR parts unless I have to, the aftermarket stuff is just as good and often better (and cheaper!) I've got wires by Accel, Borg cap & rotor, Autolite plugs, Wix filters, and I get up around 21 highway in my 88.

Since the theoretical lifespan of an O2 sensor is around 50kmiles, you might want to check yours. I think you'd only really need to change the one in teh exhaust for mileage concerns - the one after the cat is to check up and make sure it's working, the "closed loop" mode works off the front O2 sensor, IIRC.

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