speedometer bouncing

[msjjharrell]

I have a 99 Expy with 5.4 and 89K miles. Speedometer is bouncing around and sometimes shuts down vehicle if it go past 100mph when sitting idle. it only does this in Neutral, Drive, and low. Park, Reverse, and 2nd there is no needle bounce. It tries to surge when in gear when as it stumbles. Any ideas? I have seen the needles do a full sweep on occasion when this happens. No codes.

Why would it be gear dependant? That is puzzling to me.. What monitors gear selection?

 

[toms89]

I have a 99 Expy with 5.4 and 89K miles. Speedometer is bouncing around and sometimes shuts down vehicle if it go past 100mph when sitting idle. it only does this in Neutral, Drive, and low. Park, Reverse, and 2nd there is no needle bounce. It tries to surge when in gear when as it stumbles. Any ideas? I have seen the needles do a full sweep on occasion when this happens. No codes

Gauge sweeps are typical of low voltage or pcm resetting.

Bad battery, alternator, or electrical connection.

There is also a factory rev limiter set just over 100 mph unless you change or disable it via a programmer.

 

[215Expedition]

I am having the same issue with my oil pressure gauge, i think it a ground problem though.