Hello everyone. Ok so my 2007 XKR got a check engine light and the restricted performance little triangle that came on. I plugged in the scanner and get codes p300, p0302, p0304, p0306, p0308 and p0430. Can is slow taking off and when driving on the freeway feels as if the idle slightly fluctuates. Also has a hard time getting pass 55mph. Any suggestions would help. Recently changed the alternator and was having to issues until last night when these came out.