My 2001 Honda Civic LX was already having an idling problem but would drive fine once you got to a constant speed. Then all of a sudden, the RPM gage stop working, it would barely go, sputtering very badly, air conditioner got warm & i thought I seen something fly off from my car in my rear view mirror. When I crank my car, for about 15-20 sec the rpm Gage goes from the 1 to 1 1/2like 13-15 times while making a clicking noise & then levels out. I’ve replaced the cam shaft sensor, spark plugs & throttle bottle position sensor. Also the battery light comes on when you first crank it & when accelerating on the gas it bogs down with a loud popping noise from the exhaust.