My Toyota corolla 2008 Rough idle.

I'd try cleaning the throtlle body. I've seen noticable improvements in idle smoothness after cleaning all the deposits from it. Use carb cleaner, paper towels, and q-tips. Try to avoid spraying a bunch of carb cleaner down the intake, spray it in the paper towel or q-tip and use that to wipe off the deposits. Make sure to get both sides of the butterfly, it's hard to reach.

There are a lot of reasons why you are experiencing a rough idle on your car. Try to check if you have a dirty fuel injector, clogged air filters, bad spark plugs, and exhaust system issues to have it fixed.