On 8/13/2020 I had my codes read at Toyota dealer. Codes found were P1442, P1445, P2441. Found SAIS switching valve stuck closed. They recommended replacing the air pump assembly/advised replacing the air injection pump.
NOTE: I had bypass system installed by other mechanic 1.5 years earlier. Dash lights coming and going for past several months. TSP flashing light several days. Then went out. A week later the hot oil light came on and car conked out totally. Restarted and ran fine again long enough to get to dealer for work on 8/13/2020.
I am not a mechanic at all, by the way.
8/17/2020 Took car in for repairs as recommended. Tech found my aftermarket bypass wiring was causing internal communications errors between mass air flow sensor and engine control unit.
Replaced air pump assembly and disconnected aftermarket parts.
I paid the 2600. or so and brought my car home.
Next day the check engine light and 3 or 4 others lit up just as before.
It's back at dealer now. They gave me a free loaner car. They're trying to figure it out. These are quotes from my invoice. This has all become quite painful and irritating.

Babe.....do you know what bypass you had in the truck? My guess it was original Hewitt Tech version(lots of wiring). I haven't heard of many bypass issues as they are pretty simple devices. Let me know how it all turns out. I'm sure you're not wanting to install another but there are many forum members on here running my bypass with no issues what-so-ever. All of those codes you listed are easily defeated with a properly installed bypass.

Ah yes!!!!! 'Properly installed bypass'. Mine probably wasn't.
Can't say for sure. And apparently Toyota can't say either. I appreciate your help. Perhaps I shouldn't have panicked and gone to the dealer so fast. I will let you know what the dealer comes up with this time. The more educated I am about this, the better my chances for possible recovery of funds. It's not beyond my reach to question the charges on my credit card at this point. Having to take car in for same thing 3 times now is unacceptable. Thank you for your support. I'm new to this and not very good at the whole thread thing.

Get this. I got the bypass done by my mechanic 1.5 years ago at 115K miles on my 2007 V-8 limited sport edition 4.7L. Cost me 750. or so. I cannot do these things myself.
Two weeks ago I caved and gave it to dealer to fix the dash lights coming and going and car dying. So far I'm out 2500. or so to eliminate my bypass fix and put their SAIS 'fix' in. But lights keep coming on just as before.
Days go by. They haven't figured it out and have had to call Toyota.
Yes, you heard me right. The Toyota dealer had to call Toyota.
Yada Yada my 4Runner is still in the shop.
They did give me a free loaner.
Whoop-d-do.
I haven't asked my original mechanic where he got the bypass kit but I will. And I didn't find this thread until I was out the major bux.
I do thank all of you out there for your clues, etc.
Again. I am NOT a mechanic. I'm older. I'm female. I'm the original owner.

Back in 2019 I had the SAIS bypass done with block plates. Within a year the codes returned and after months of unreliable driving I went to Toyota dealer because I wanted it back to specs. My 4Runner was build in 10/06. It's a V-8 Ltd. with 125K miles.

The Toyota dealer installed the correct system and it cost me even more to have the blocking plates removed. But now my 4Runner runs like new. More power. Sure it cost me but I'm the original owner and have taken care of it. You can be sure that all my repairs will be done at dealer from now on.

So what did you wind up doing??????

I have the bypass kit on my desk. I had it uninstalled at Toyota dealer and the correct system put in because I wasn't going to deal with returning codes and 4Runner going limp. I'm very happy with results. It has it's original V-8 power. I need it to be 100% reliable. And I don't work on it myself.

I'm attaching 2 photos. What can you tell me about what you see?

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That appears to be a Hewitt Tech kit. Shape and Purple wire are "identifiers". I will send you a PM as well.

In my case I had to rely on a service station mechanic to install the bypass. In the process he broke some bolt putting the block plates in. I am at mercy of others unfortunately here. Toyota dealer finally figured it out. They were unaware of the bypass plates but finally found them and fixed the bolt in the process. I believe they should have researched these systems online but they didn't charge me for keeping it all that time because it stumped them. My particular dealer had never seen one of these installed. It is unfair for us V-8 owners to have to shell out this kind of money. I do have a case open with Toyota but with 125k miles I don't expect any reimbursement.
They gave me a free 2020 4runner loaner for the 2 weeks they had my 2007. I'm going to give my 2007 to my husband and get a new one next year.

It just started doing it again, seems to be only an issue in cold weather on mine. I ordered the block off plates but never installed them because it stopped recurring when the weather warmed. Will have to install at some point now.

This only happened when cold and it started again this year so I finally got around to installing the blockoff plates the other week. Seems to have solved the problem. If any future searchers are borderline on needing the plates and debating install I can only say do it while you still can, one nut on the driver's side is a real PITA when it starts to rust, almost stripped it. Mapp torch with a hose quenched with lube right after will make your life easier. Plus a medium-deep socket, sharp angle swivel and bunch of extensions. The kit itself is quality all around at a good price though