Ive got an 05 4Runner with about 220K miles with the 4.7L and I was doing the intake manifold gasket, and valve cover gaskets about a month ago and the bolts holding the valve cover together all 4 actually on the bottom side sheared off, leaving just the thread part left (Very rusted and stuck in the hole. Could grab it or any sort so I took it to a shop and the guy tried bunch of different things including, welding a nut on it to just twist off (he said it didnt work, but I feel like thats a good way and best but I take him at his word.)

Guy said last resort is drill em out. Meaning he has to pull the engine up and out to be able to get a drill in there. and he said $350 for it all. I feel like thats a great price but if all the trouble to pull the engine out just for this.

I feel like its a case where while its out let me do these things before I put it back in. Timing Belt, gaskets, old hardware, etc. Or I was told the floating idea around about rebuilding it and making it "new" again. I think me and a couple of buddies could tackle the task. Just looking for some other opinions. Great car, perfect for everything I use it for and looking to keep it in the long run.

I am far from a seasoned mechanic, especially on the 2UZ as I have only recently had one but in my experience if the engine is running well Id recommend against a rebuild. Hows yours doing at this time?

Hard to say because I have only owned the car since 210K miles and about a year. Service records are not the most kept up on until I bought it. I had a P0171 and P0174 for the longest time, but since I have to pull the engine out anything that would be good preventative maintenance

Those 2 codes are indicative of the intake manifold gasket being bad and why you were having it replaced.

Do you have the aluminum intake or the plastic intake? Not sure what the 05 had. Be a good time to swap to the plastic intake if you have the former. Lighter by like almost 20 lbs, will give you better mid-range and top end performance as well. Direct bolt on and you just need to get the throttle body that goes with it and flip it upside down. Block a couple of vacuum ports and hook a couple others up and you're in business. I did this on my 2003. Works great.

If you are pulling the engine, do the timing belt and water pump. Don't bother with a complete rebuild. If you've driven it 10k miles in that year and it's run good, just had those codes, then you should be fine and have a decent idea of whether it runs good or not.

Also replace the valve cover gaskets and any rubber hoses that aren't soft any longer. Mine had a bunch of hoses that were rock solid and needed replacing.

Check the exhaust manifolds for cracks. Maybe replace with headers if you have the spare coin for it. Also rebuild or replace the starter since the intake is off. Go with OEM Toyota if you replace it.

Do you have a detailed
write up or have link to one on swapping the VVTI plastic intake manifold to the 03-04 models. Thanks in advance!

Click the link for my build thread in my signature. Not super detailed since I was also doing valve cover gaskets and the timing belt and water pump at the same time but all the information is there.