Originally Posted by jkulysses
Just order a manifold for a 2002 model as Toyota started putting basically a mini header on there from 02' on. It will bolt right up and is the only true fix. Should be able to get a factory oem upgraded manifold with new gaskets etc for around $250 which is still much cheaper than buying an actual header that doesn't really give you any more gains than the oem manifold.
Here are all the Toyota part #'s you'll need:
Header part # 17141-75080
Donut gaskets which you will need 2 of these part # 90917-06061
manifold gasket part # 17173-75020
egr gasket part # 25634-75010
that's if you have the 2.4 or the 2.7 engine, with it being a prerunner it should be the 2.7 I think. (disregard our advice if you have the 3.4 v6 engine)
you can get these manifolds at salvage yards and save a lot of money plus not have to buy and install the studs in them (3 at tail pipe plus 2 at the EGR pipe fitting)
these manifolds are thick steel wall tubing and last forever so the one from a salvage yard will last just as long as a brand new one but only cost 1/3rd the price, plus at the salvage yard you get the heat shield and the bolts for that too.
look here for your manifold: http://www.lkqpickyourpart.com/locat...-_Chicago-581/
if you cant find one then buy one new, you are looking for an exhaust manifold from a 2002-2004 Tacoma
whatever you do DO NOT BUY A CAST IRON REPLACEMENT they are all garbage and will crack again in a few years