I am new to this forum as I never had any problems before with my wife's 2001 EX-L V6 3.0 with app. 140000 miles. I changed oil today and was in a hurry to finish before dark so I could test drive to check noise from front end (which I think is CV joints). I checked oil level and it was slightly over full but thought it would be alright to correct after test drive. I drove app. 5miles and engine started to run rough and check engine light was flashing. Car idles rough now too! I drained oil and found I was about 1 qt. too full. If this caused the rough running, what damage might have been done. This is my first post ever so hope I am doing this right! Thanks.

 

Your oil can be slightly high. If it gets too high, the crankshaft and connecting rods will contact the oil. It is unlikely that you did engine damage, but I would correct the level before driving any more.

I would grab a clean container, then drain enough to get the oil to the proper mark. If you drain too much, just add some of the oil you collected till it reaches the upper limit.