tune up 2007 corolla
what should a tune up consist of?
Spark plugs and filters. New coils only if they are bad.
My idle appears to be a bit lower than normal. It is hovering around 550 rpm in gear under 800 out of gear. The engine vibrates a bit at a stop while in gear. 240,000 miles on the car. Never had to change any of the coils. Is it possible that they could be going bad, but not yet thrown any engine codes? Can I check resistance? If so, what test points are there and what are the values I should be looking for? Any other advice on tuning the car would be appreciated. Thanks!