StreetzINC

My maxima is misfiring and the pipes on the exhaust manifold behind the front cat is turning fire red. I have replaced all the coils and spark plugs, the result i still was misfiring. I replaced the EGR valve, the result i still was misfiring. Checked the cam and all crank sensors i know about and they were fine. The MAF is also working fine. The car still has good power and it will accelerate quite nicely. The idle is rough and it is puting @ the exhaust. I also hear spark knock r spark rattle whatever it is i dont like it. The car also warms up quickly but it never overheats and i smell more gas than normal under the hood. The idle gets rougher once the car is completly warmed up. Can anyone help me narrow down my problem r help me find the problem.