Engine/Transmission (1998.5 - 2002) Rough Idle

[PKirby]

A friend has a 1999 24 valve with approx 200k miles. It has developed a rough idle that can only be felt slightly but can be heard from the exhaust. It seems to be smooth when cold and smoothes out when not at idle. There are no trouble codes. Any ideas?

Thanks.

 

[trqmnstr]

Valve adjustment???