Rough idle in park

[BLUEBLOTCH]

i have a bit of a rought idle when in park, what are some of the most common things that cause this? BTW my car is stock except for K&N filter .Thanks.

 

[ddavisaf]

Run a Boost Leak Test.
Make sure your spark plugs are NGK BPR6ES gapped at .028".
Make sure your fuel filter has been changed within the last decade.
Check your plug wires.
Test your ISC.
Test your TPS.
Clean your Throttle Body.

And read this.