I have a 94 Integra GSR with about 230K miles. In the last month or so I get what sounds like valve ping when I take my foot off the accelerator. Originally it didn't make this noise when accelerating, but it does now a little bit. I checked the valves, which needed some adjustment, but it didn't make any difference. I made sure the oil was not low. I've searched this site and the Internet and haven't found anything. Anyone know what can cause this problem? Timing, vacuum leak, etc.? I'm wondering if it's an initial sign of the engine wearing out.