Hi

I have 94 Nissan Altima. I noticed that in the morning (when car is cold), when I start my car speedometer shows speed of 40 mph and odometer also moves up as if I am driving at 40 mph. Ideal speed is low (1000 rpm). I don't see this problem when car is warm.

Any idea what could be the problem. Is it something to do with trasmission?

Thanks

NM