When is the last time you pulled your front brakes apart and cleaned them?
Clean, grease pins, compress pistons etc. make sure everything is moving properly.
Check for bearing play in the fronts....did you replace the lbj's yet?
Couple listed here...
http://www.toyota-4runner.org/3rd-gen-t4rs/7501-programming-instructions-keyless-entry-remote.html
I'd check that ECU and see if it's labeled with it.
It won't be pulled into the engine through the pcv hose.
Use the line off the vacuum booster if yours has one.
Edit: guess it must not.
I think it's only worth putting in your gas tank personally.
If you drive your vehicle more than a couple times a week for ten or more miles and everything...
I just ran the part number through 1sttoyotaparts and it had it listed....could try and order it, I've never heard they were discontinued.
77701-35010
I bet you could achieve the same thing by putting a inline metal or plastic fuel filter on the hose.
Most these newer vehicles (2003-04ish) require the Toyota TIS OBDII interface to "reset" things after a battery change/loss of charge/etc.
Find someone with a DVOM that knows how to use it.
The 4wd's are not as easy to get out.
The solenoid are usually the issue when you get a click or just nothing. He fixed his for about 40 dollars and the OEM Denso starter is higher quality then what most part houses have. How much did you spend on an aftermarket starter?