My 95 Honda Civic surging while idling. It all began when during a rain storm when I drove through a long puddle of water on the road. At the end of the puddle my car switched of, but after a couple of cranks it finally came to life again and drove normally. The next day, when I was driving home from work I noticed that the check engine light was on. My Honda has 224K on it and the check engine has NEVER been on since I've owned the car. It was also at that point that I noticed the car started to surge while idling. I took it to a repair shop and they said the car was running lean(what ever that means) and suggested I change the fuel filter which I did. This did not solve the problem, my car still surges. My check engine light now turns on and off intermittently. Sometimes when I get to a traffic light and it is on, I switch off the car and switch it back on again and the check engine light does not come on again until sometime later. However, the surging idle is always there, this does not go away. PLEASE HELP with your advice and experience on how to solve this problem. Thanks in advance...

Check for codes, by jumping the Service Check Connector. It wouldn't surprise me if the code check indicates the oxygen sensor needs replacing. If it does, only buy a Denso replacement.