Those of you who know me already know I have an addiction to Toyota Trucks. Their compact size, Their indestructible construction (aside from body rust) and their bullet proof driveline make them high on my list of must have outdoor adventure vehicles. I've been though a couple first generation and second generation 4runners in the past few years and the only complaint is They're damn slow!!
There's not much that can be done in a conventional "tuner" sense being that the ECU is very primitive and very locked down. so what can be done in DIY land??
some simple fixes include getting a K+N drop in filter K&N 33-2031-2 Replacement Air Filter and advancing the spark Timing (a timing light needed, and basic understanding of what this can do to your engine.) Tooluxe Tools Xenon Automotive Timing Light
one common problem on the two standard (canadian market) Toyota truck engines, the 22re 2.4 L4 and the 3vze 3.0 V6 is the intake path. usually abnormally long and full of bends, they tend to be kindof lacking in the airflow category.
The DIY fix for the 22re intake, is to relocate the airbox and battery to opposite sides of the engine bay. This entails a few things, the battery cables must be lengthened for the EFI controls, any accessories running off the battery (ie. fog laps, stereos) and the starter. And the intake must be shortened. I accomplished the intake shortening by taking the plastic over the Rad tube out and simply hose clamping the two rubber ends together resulting in about 2 - 3 feet less intake path from the airbox to the throttle body. this can also be accomplished with PVC pipe and silicone couplers for a few more dollars Vibrant 12700 Silicone Coupler 3" ID x 3" Long Black
On the 3vze the best method for improving the intake is to remove the intake silencer/ air bypass source box and replacing all the rubber tubing with PVC pipe from home depot, and silicone couplersVibrant 12700 Silicone Coupler 3" ID x 3" Long Black from any auto parts stores. this results in a more direct airflow to the Thottle body.
Another power taker (this is debateable) is the old mechanical cooling fan bolted onto the water pump. This can be replaced with a 90's ford taurus rad fan from pick your part (best physical fit for both engines) or a Flex-a-lite 398 Syclone Black 16" S-Blade Reversible Electric Fan and a simple princess auto relay kit (manual control, meaning watch the temperature). If you feel like putting about 36 bucks into this setup, you can get an adjustable control module from a few online sources like amazon.com Flex-a-lite 31147 Adjustable Temperature Control Unit. This modification should noticable reduce engine noise, and improve throttle reponse.
Finally the third most noticeable improvement would be exhaust. on the 22re the exhaust manifold is not the problem, it actually flows quite well. The problem is the collector (the pipes the manifold bolts to) and the piping from the collector. This can be fixed by having a muffler shop build a nice large collector (out of a single 3 inch pipe bent to fit) to replace the two tiny collector pipes, and have that connect to the stock manifold connector, and run 2.5 inch pipe all the way back. Run some low cost cherry bomb muffler and you're set. Cherry Bomb 16803 Turbo MufflerThis will provide some over the hill on the highway power for the little 22re.
The 3vze on the other hand is a little more extensive. A lot of people will argue, get headers get headers. to me, that's just too expensive. The best bet for the 3vze is to eliminate the crossover pipe from behind the heads and have the passenger pipe run to the main exhaust right before the O2 sensor (instead of the engine bay) then block off the "incoming" collector pipe on the drivers side manifold. the will help in 2 ways. Lower under hood temperature, and removing the backward flow of the crossover pipe. This will allow the v6 a little breathing room.
If you're fortunate enough to live in an area that doesn't have emissions testing, or if the truck is Off-Road only, then you can get away with a bit more breathing room by eliminating alot of the emissions gear, such as the catalytic converter (exhaust restriction) the EGR (exhaust gas recirculation) which raises intake temperature and increases carbon build-up. and removing the SAI pump and plumbing (simply for cold start emissions control, but probably about 15 feet of tubing and vaccuum lines just for this system).
So with the listed tricks I've personally noticed throttle response and a bit more driveable power. Numbers, don't have any, but it feels better and didn't break anything, and thats what matters. They are Toy's for a reason.
If anything I've written doesn't make sense, or you don't agree with, then comment about it dammit. And either way its getting you under the hood to DIY.