Is this normal? 2000 5.4 when she starts cold the rpm's run about 900. But when I shift to reverse it jumps to about 1200 and when going from reverse to neutral back down to 900. Then when shifting to drive way up to 1500. In both reverse and drive it only stays up for a second or two and back down to 900. After that she runs smooth, I let her idle in park for 30 seconds each time to allow oil to circulate and warm a bit.