Lately, my 1999 Civic LX has developed an intermittent problem. When I start the car when it's completely cold, I'l drive off in about 30 seconds. When I push in the clutch and come to a stop sign, the RPMS will go from fast idle (like 1500 RPM) to about 50 RPM. The car sounds like it's choking. The weird thing is though, the RPMS will drop really low then in about a second, rise right back up to normal warm-up RPM. It only does this once, and when it's warmed up, it never does it again. It's only when the car is started cold. Some type of sensor I would think..

 

bumpp