I have a 95 f150 5.0 5speed 4wd. 143,000 miles. Upon start up it will idle up and down several times. Then once in gear it will high idle for a minute then level out. When driving down the road it seems to idle down and kinda stumble in the upper end of the gear. But if I down shift and give it more throttle it will pick right back up. It does have an exhaust leak on the passenger side manifold and I’ll be replacing it soon just needing some ideas on what to start with.

 

I would address the manifold issue first then diagnose as needed afterwards. Any leaks upstream from the O2 sensor(s) will affect the information they send for proper air/fuel mix..

 

Sounds like a throttle position sensor....????