Thanks for the help,

2002 150 5.4

when started cold the idol is rough with the 301 and 306 code. Once operating temp is reached it runs fine with no misfire. The cops and plugs have been changed on both. What is the next ave to explore? A airaid cold air intake lets you hear a blast of air with every miss.

Thanks for any input.

 

Need some info.
At inital cold start does it go to high idle?
If yes, how long to come down to normal idle speed of about 750 rpm.
Has the intake air sensor been put back on the new intake tube?
The reason for the questions is a suspect the cold start mixture is too lean until the temp gets up where the OX sensors take over fuel control then it smooths, out as you indicate.
We need something to point to as the cause.
It may even be the new intake tube/filter.
If the mass air meter has had it's airflow altered such that it's metering is now out of limits., it could be the cause.
Is the fan possibly blowing onto the filter in some way?
Good luck.