Hello, I have a 2001 Mustang Gt. I recently just installed new BBK 73mm throttle body/plenum combo. Before the install car ran perfect would start And idle just fine on cold start. Now, after the install car will start but does not want to hold idle. It raises about 900 then drops to about 300 then back up to around 700 then back down to 300 and dies. If I start it back and feather the gas For about a minute, it will idle like nothing is wrong, only having the issue when cold and first started. I have a K@N FIPK cai and custom exhaust. Have went over and checked all vacuum lines and iAC and tps everything seem tight and in place. Any advice ?