Results from searching were vague.

My car will start without issue and has full power until ~4k RPM. It wont rev past that however there is no problems with the engine UNTIL then. I've read this is 5th/6th port territory but it shoulnd't stop my engine from revving, just make it hessitate, right?

 

Read the FAQ about grounds, it sounds like that's it.

 

Thanks - that didin't occur to me as likely until you mentioned it

 

I had a similar problem with my secondary fuel injectors clogged. The car would not rev past 4k. (Well actually, it did but very slowly.) When I had the extention manifold off I was cleaning it using some carb cleaner. The dissolved crap ran down and piled up on the secondaries. After some hard driving, the clog blew out and everything was cool.

I don't know if that's what your problem is, but it's something to check.