TP123

My 2004 rx8 has 85k miles but 5k on the "new" reman. engine, I just had the spark plugs replaced about 2k miles ago. My car will not go past 5k rpms and it dies if I don't continue to give it gas. I thought the problem was a clogged cat so I removed the catalytic converter and it didn't change anything. I plugged in a scanner and got the misfire in cylinder 2 (or rear rotor) and a stuck intake manifold valve codes. It will only drive for about 2 miles before it just dies on me while driving, so I can't drive it anywhere and the cat is off so it is ridiculously loud atm (until I get a midpipe) so I am trying to fix this by myself so I don't have to pay for a tow to Mazda and then get charged an arm or leg.

Thanks for the help in advance

-Troy