We have a 2001 ford F-150 with 5.4 engine and automatic trans.

When sitting still in park at approx 1900 rpm there is slight vibration. The customer originally took it to the local Ford dealer who replaced the drive shaft which of course did not fix it. The vibration is felt the dash and seat but is not a real bad vibration and we are unable to pinpoint an exact source.

We have checked for engine codes and there are none set. We are stumped as to what to look at next. If anyone has run into this problem we would sure appreciate some direction.

 

Have you checked to see if the exhaust may be loose? I had this problem with my 97 a month ago and it was the exhaust, It would vibrate when in park and in reverse but completely dissapeared when driving.

 

The rpm's at idle seem to be too high. My truck idles at 1,000 rpm's until it warms up, usually about 30 seconds or so, then it drops to about 700 rpm's. Hard to say if the vibration is related to the rpm's or not, but it is possible.

 

bent fan blade? loose pulley on engine, harmonic balancer? hope you figger it out.