first thing, we took this engine out of my friends lude and put it in my sol. everytihng worked good when we took it out. i think im running rich. my plugs are black. not sure why. we changed the timing belt and everything looks to be lined up perfect my car idles smooth. but im throwing a code 14. IAC. when i give it gas and hold it at a certian rpm. instead of being a smooth VROOOOOOOOOOOOOM it goes VROM VROM VROM VROM. all choppy. im still trying to bleed my coolant system. its like theres nothign but air in there. could my ecu have gone to shit? thanks for any help.