Rough idle in gear only/warm engine

See the p0506, I don't know if low idle speed is your problem? You can see the system description. you can clean the throttle bore and around throttle plate, don't force the throttle plate. How many miles on your engine? You have good cylinder compression? With transmission in park or neutral, not much load on engine, higher rpms. With transmission in gear, there is a load on engine, rpms lower. Any applicable trouble codes?

Look over vacuum lines, at that age the hoses can become brittle and crack which can cause a number of different issues with rough idle being one of them

There is no error codes,hoses, compression, etc good. Approx 140,000 miles. I can just barely increase rpm's and it's smooth. It started after a oil change, so I'm wondering if something could of got bumped or not....idk

140k miles....how much slack in throttle cables?

Also....what rpm is it idling at?

When warm idles around 1000 rpm in park and neutral. In gear drops to 800. No slack in throttle cable.