Mk1 2ZZ swap: used to work fine, now won't rev above 5k?

[labcoatguy]

First off, apologies about starting off my first post with a request for help; I can only hope that I can become a net asset to this board in the future.

Situation: 1988 Mk1 MR2 with a 2ZZ swap from previous owner, has been running fine for about two years, kicking into lift like whoa as expected. All stock electronics with the factory Denso MAF in the intake piping and an O2 sensor installed after the header merge.

This summer, it started to seriously lose power and bog down on hot days, occasionally even stalling when stopped. Here's what I did next:

-Suspected knocking, added octane booster to the next fillup and cleaned the MAF with MAF cleaner spray, and after putting it back in, that's when it stopped revving above 5k as if a rev limiter kicked in at that RPM.
-Later found that the MAF mount had separated from the intake tube (JB weld failure), fixed that, but not before panic-buying a new MAF sensor and crank position sensor.
-Installed them, still wouldn't rev above 5k, and got P0171 and P0325 codes (might've been left over from beforehand).
-Disconnected the battery to clear codes, went out for another drive, doesn't bog down as much but still can't rev above 5k.
-Read the codes again and the only thing that came up was an evap system code and a bank 2 O2 sensor code, which I'd expect, as the guy's swap didn't include those two parts.

I wonder if the ECU just needs to cycle a few times before letting itself get above 5k again. On the advice of others, I've tested out the upstream O2 sensor, the coolant temperature sensor (the one in the head), and the camshaft position sensor, and all of them have resistances in the normal range, so for the time being I'm ruling them out.

Interestingly, somebody on Youtube seems to have the same problem, and claims to have fixed it by replacing the camshaft position sensor, but mine seems to be fine, at least according to my multimeter.
[youtube:3082pynm]zDYOWVvOZQw[/youtube:3082pynm]
So, gurus of MR2ROC, what say you?

[lamcote]

Is this any help?

 l viewtopic.php?f=11&t=62867 l

[labcoatguy]

Yes, it completely solved it. Turns out the bolt on the crank position sensor was loose and the earth wasn't connecting. Tightened it down and it revs to the sky again. Thank you very much!