This thread is a tad old but I wanted to bring up a point about starters. Generally speaking, when a starter starts to act up, it'll show symptoms like click, click, click or super slow starting even with a fresh new battery. So, I don't think I'd call this "borrowed time" because you do get some warning.

I'm at 380k and I don't know if this is the original starter or not but it's still going strong!

I completed the secondary air injection system repair over the past week or two on my 2008 4runner and wanted to share my thoughts.

1. I ended up doing the actual repair because I felt like the bypass is a half hearted repair. To each his own, but my personal preference was to do it correctly, additionally my check valve was stuck open and I felt like the best fix would be to get in there and replace the whole system

2. I bought most of my parts from the dealership, with the exception of the Pump which came from O'Reilly. The dealer had some reasonable prices for most parts, but the pump itself from the dealer was somewhere around 400. I bought the pump that was a complete unit, some you have to swap half of the old pump over apparently.

3. I did not remove the coolant bar, I went with the method from the video, with the shallow sockets with the exception of when removing the bolts that bolt the check valve to the coolant bar, I put one of my sockets on that had a hole on the side of it, and then stuck a narrow long screwdriver through that hole. There was no way to reliably torque the bolts back there, so I had to go by feel.

4. I missed one plug, on the drivers side near the very back of the intake manifold and it threw code P2433- if anyone gets this code after completing this repair make sure all your plugs are connected

5. Be careful with the connectors that connect to the pump and valves, I broke two, however, I broke them while applying only finger pressure, so I'm not sure if being careful will do you any good. This seems to be common, I guess because of the heat I ended up zip tying these connectors back on. I will purchase replacement plugs and plan to repair them if and when I go back in there. You have to get a little creative with the zip ties. I thought that this was the reason for my error code originally and I was going to have to redo the repair

6. I ended up replacing the rubber hoses that make up this system. Mine were dry and brittle after 164k miles

7. I'm glad to have the advice on the o-ring. I thought about reusing mine. but ultimately didn't because of the advice in this thread.

Well the rear coolant crossover started to leak, so I followed this guide and replaced the starter and the rear coolant gaskets. A few quick suggestions:

-Replace the front coolant crossover while you are in there, the gaskets are the same part number as the rear, so just buy four instead of two. Speaking of o-rings, you'll need to remove the thermostat housing to get to the front crossover, so buy a new o-ring and some RTV for that piece as well
-If anyone tends to lose bolts like I do, the ones that attach the exhaust pipes to the SAIS valves are M6x1.0 and roughly 20mm (I managed to lose two of them so my recommendation is to just buy some extra)
-Put a towel or something soft over the radiator/front of the truck so it is more comfortable to reach the back of the engine.
-Replace all the vacuum tubes while you are there, they are 5/32" tubing, I ended up needing two of the packs that Autozone sells
-I don't see why the shop manual says to remove the injectors and fuel rails, I didn't and the intake manifold bolts are still easy to get to and everything came off just fine.
-Taking the pump and diverter valve out is really easy, just remove the four bolts that hold the bottom plate to the engine and it wiggles out (I had to cut the tube that connects it to the rear crossover to get it out)

Overall, plan on this taking two days to do. I have done the timing belt twice, and found this to be much more difficult/time consuming. Granted I made lots of mistakes along the way and had to do things over several times, so your mileage may vary.

Thanks for the awesome write up!

Great guide. Note that this guide will work for the 03-04 non-VVTi 2UZ engines as well. All the steps are the same, those engines just don't have the air injection junk to worry about.

A note on the starters and when to replace them. I'd say that if you are taking the intake manifold off to do the repairs in this guide, replace the starter while you are in there, whether it has issues or not. Think of it as preventative maintenance. Not often will you need to gank the intake manifold off, so you might as well replace the starter with a new/rebuilt one while your in there. I highly recommend a Denso replacement instead of an off brand. Denso is the OEM brand and even if it's a rebuild, they are proven reliable.

This guide was helpful, thanks! I got the p0333 code but it wasn't rodent damage. the sensor passed the tap test, and the resistance looking into the ECU was about 250k ohms, same as the right side knock sensor input. I replaced both sensors with Toyota parts. It's been fine for a couple weeks now. Moral of the story: the knock sensors could be bad even if they pass the tap test. Other posts said sometimes aftermarket sensors don't fix the code.

I've got a video of this job coming soon. If I remember, I'll edit this post and link the video.

Thank you for this!!! I'm replacing only my check valves, after confirming one was broken and my SAIS Pump and Switching Valve are functioning as normal.

We've wiggled this pipe w/ the O-ring and I kept thinking, "maybe we just replace it... just to be safe." I will heed your advice and get the thing renewed. also replacing a couple of hoses that cracked slightly when reinstalling the AIR Switching valve, for good measure.