I have a 2001 f150 5.4l 4x4 4r70w trans. with 71000 miles. When the engine is cold and I change from park to reverse ther idle climbs up approx. 300-400 rpm and then drops into gear. It is lower when the engine is warm or when shifting from reverse to park. Trans fluid looked fine changed anyway. Pulls strong through all gears and does not slip. Is this a problem? Seems like the rpm should not climb that much to me between gears. I am afraid it is going to break a u-joint. I just bought the truck. So I cannot say how long it has been this way. The engine starts at approx. 1100 rpm, and decreases the idle normally as the engine warms up. Idles when warm around 700 or so. So I don't think it is the IAC.

Thanks
Frank

 

Clean your IAC, MAF, and throttle body.

 

^^^yup