i put an h23 in my sol. and im still having some problems. when i try holding it at a certian rpm it doesnt stay smooth. its very choppy. also, sometimes itll just bog down instead of rising up in rpms. what the hell is wrong.....(oh yeah, im also throwing code 12 and 14. i dont have the egr hooked up. (yet) and my IAC appears to be fine. the idle is smooth. when i unplug it then it goes crazy, when i plug it in, its fine...whys it still throwing the code?) p.s. timing is on.