First off I would ditch the throttle body spacer and cold air intake idea. You should do the deck plate mod(lots of info on the net on this one) instead and get a reuseable air cleaner. Lot cheaper, just as good IMO.

Next if your getting shocks bite the bullet and buy Bilsteins, these shocks work great on Tacos.

As far as lift, is it really worth it for 1"? I thought about it myself and decided no.

Go to Autozone and rent the code scanner and use it next time the check engine light comes on. It will tell you exactly whats going on.

Good luck.