Helpful until they weren't. Had my car in for a timing adjustment as the CEL code was indicating that it was over-retarded. After the timing adjustment the code is still popping just not as frequently. This indicates that it is "More" in time, just still slightly out. I would do this repair myself, and am now going to have to attempt to, but I do not have the right tools for the job. They want to look at replacing other components which on this specific car run anywhere from $400 to $600 without labor included. I have on extremely good authority that the timing is still off, needing to be advanced by 1 or 2 degrees, and the Charlie's tech will not go over the timing again to make the adjustment.