Weird speed limiting... knock sensor?

[JdrifterCA]

Ok, just got my sr20det like 1000 miles ago. lolz i put 1000miles on her in a week hehehe. anyways it pulls hard, runs fine.... but when im going uphill, in 5th gear going 70ish the speed limiter kick in. It felt like a speed limiter cuz the car just lost power and than regain after slowing down a lil. I than regain speed and than it kciked in at 80mph, after that i kept my speed at 75. But normally it goes over 110 no problems, but every once a while i get that speed limiter/ fuel cut off.... any idea of wut it could it. Is it the knock sensor trying to protect my car? im runing on 91 octane. please help

[wzntha]

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[JdrifterCA]

Going up hill, 30% throttle. as u accelerated to 80mph a sudden loss of power. Felt just like the speedlimiter on my old ka. I have a warlbo 255fuel pump btw. and im pretty sure is on correctly