For the past couple of months, my '94 Accord EX (120,000 K miles) is pinging
when I lay off acceleration at 30 to 40 mph. No problem under accleration,
only when maintaining speed. Oil change is recent, plugs are in good shape,
valve clearance adjustment in last 5K miles. Using 92 octane helps but is
not a long term solution. Should I look at the timing, EGR ports? Thanks.