My delta royale which I recently purchased has a rough idle. The previous owner said he did tune-up 6 months ago. Could it be something simple like plugs or wires or is it something bigger? I should mention that the rough idle is more noticeable when the car is in drive . When its in park I hardly notice it. Should I be worried or should I just leave it alone as it seems to run fine, its that that little things like that bother me.
Thanks for any input.

My experience is check the PCV EGR and O2 sensor people tend not to include those in a tune up.

I replaced my O2 just recently and it idles a lot better.

thanks

A "Tune-up" can mean different things to different people today. I would remove one of the plugs to see the condition of it. Is the gap correct? What kind of spark plug did the former owner replace it with. I personally use the regular AC-Delco plugs(R45LTS6) in my 91 Olds. You didn't say what year your Royale was. Also, you might want to look at the Air Filter to see if that was changed as well. If it was 6 months ago than it should look almost new(depending where and how far the car has been drivin in that time). I suspect it may be time to replace the ignition wires. Everybody here has there favorites but at the very least replace them with AC-Delco wires. Also, it would be a good idea to clean the Throttle Body. Hint, you can't do it with throwing in a can of fuel injector cleaner in your gas tank. But that can't hurt either. Let us know what you find and I'm sure the members here will get rid of your miss or missus.