SSNixon

At idle, my car sometimes shakes and sounds rough yet my car is not throwing a code. I replaced both Bank 1 and 2 air check valves because my car showed those codes but that didnt help much if any (it just turned the SES light off). My car has 86,000 miles on it. I could probably find it myself, but i dont wanna do the guess and check method, wasting time and money. Are there any simple proceedures i should check first before i go and start buying parts that "could" fix the problem?
Not sure if this could relate, but my engine at high RPMs also make a slight crackling noise from under the hood, dont know if this is really considered pinging or detination but it just doesnt sound right.
Please let me know anything about either one of these problems if not both. Thanks guys.