code 28,

[Rick]

I found out what code 28 is, Knock sensor, so now what? This car sat for some unkown time period, posted a question on this lifter sound. Ran seafoam thru the oil, the lifter noise went away. Now the noise is back, at idle it is pretty loud, now when you are in drive and get up in RPM's the sound almost goes all away. Let off the gas and you can hear it again, going crazy here with this, changed oil again, noise went away for a few mintes after driving 5 miles, but once again came back. Any ideas help
Or should just burn it and collect the insurance. just kidding, also have code 56 egr system, car did come from Ca