My cousin had an E -cam on his 89 coupe and the car ran and idled fine. The engine is stock except for the pullies and exhaust. He decided to buy an f -cam and swapped it in. Ever since the cam change, it won't idle steadily, then it dies. It runs rich because the plugs are all black when we check em. The only thing he did was swap the cam and nothing else. Since then he replaced the plugs, cap and rotor, new o2's, map sensor,tfi module,tried the air meter off my coupe, new tps,new iac,timing is at 14,new egr, and still it runs rich and has an erratic idle.If he floors it, the car runs strong but it wont idle and runs rich. The fuel pump is new and we tried a different fuel rail incase the old pressure regulator went bad.He tried different injectors that are all in good shape. It has no vacuum leaks either cuz we double checked those also.We just about gave up!! It's not the cam because I just installed an f-cam about a month ago and mine runs fine. I had an E- cam before too. Let me know if there is anything else we have overlooked. We are curently pulling codes.. Thanks for any help or advice you can give us.....