Drivers side in a rich condition

[mikeaford]

So down to the basics I need some thoughts here! I have an 01 trans am built all forged internals stage 2 heads L.T. headers hight flow cats magnaflow exhaust slightly larger than stock cam (nothing rediculous). Car was running fine then after cleaning the KnN filter car started to surge now it only does it when warmed up driving fine till 20 to 40 minutes then it surges and you here a low sputter from the exhaust - if you hit the gas it clears up but power is definitely not there.
I pulled the MAF sensor cleaned with MAF cleaner, still surged. I took it up to the shop they hooked a laptop up and we went for a drive. He stated it looked on EFI live as if there was an exhaust leak. past the O2 sensor. they fogged the exhaust and saw no leaks, they then fogged the intake and noticed some fog escaping from under the intake. All intake gaskets were then replaced the fogged to check for leaks. I was on my way back home and it started surging again after about 45 minutes.
I went home cleaned the MAF sensor again, and the A.I.T sensor, map sensor and inspected the Throttle position sensor I cleaned the throttle body and pulled a spark plug for cylinder #5. Spark plug was BLACK - completely fouled. I pulled all spark plugs 1,3,5,7 aka drivers side were all fouled! 2,4,6,8 looked normal as could be. I replaced all of the plugs 1-8 and went for a long drive (approximately 120 miles) - however it is STILL doing it? O2 sensors are new (approximately 1800 miles on them). Any thoughts? I was thinking of swapping the O2 sensors and see if the condition "jumped" to the other side what do you think? Have you ever had this happen - ANY help / suggestions are GREATLY appreciated. I want my car to have power and run good = but not happening right now! Thanks!!!

[Pete Rock98]

The injector could be stuck open pour a can of seafoam in the tank...Also swtich the 02's sensors from left too right .Then check the spark plug wire on # 5 switch it with one from the other side of the motor .Last check the ground straps on the heads make sure when they are secured.Sometimes went people swap heads they forget to attach them.