
I have a 1999 Nissan Maxima with 150K mi on it. Today the check engine light came on and when I slow down the engine almost dies. It died once today, but most of the time it catches itself and revs back up. When sitting at a light it's idling around 550 and is very rough. I pulled the codes tonight and I'm getting 0102 (Mass Air Flow Sensor or circuit fault) and 0304 (Knock sensor or circuit fault). I had this same problem a few months ago, but was getting a Throttle Position Sensor error code along with the Knock Sensor code. I replaced the TPS and the check engine light went off until now. My question is do you think its the MAF sensor or the Knock Sensor causing the problem? I've read other problems cause the Knock sensor to come in. If its the MAF sensor do you recommend cleaning it or should it be replaced?