When I'm driving 40+ mph and ease up on the accelater the engine slows like you turned off the key and when you press the acceleter it seems to run again, of course there is a jerk which I'm sure it isn't good for the drive train. Has anyone else had a problem like this? Thanks

 

Welcome to the forum

I assume its a Ranger with an automatic transmission?

What year and what engine?

Engine computer(PCM) will shut off fuel injectors when "coasting" as long as RPMs are above 1,500, it saves on fuel
But there should be no lurch when you press down on gas pedal

Could be a clutch issue inside the automatic transmission.
As long as you are "in gear" then engine RPMs should stay high when coasting as you are in essence using the engine compression as a "brake" to slow down.
If a clutch is releasing input shaft then engine RPMs will drop to idle, like if you shifted to Neutral while still "coasting" at 40mph, and that should not happen while trans is in gear.
If it did you would get a lurch when you pressed gas pedal as the clutch re-engaged

Year and engine would tell us the transmission you have

 

Thanks for the reply. My truck is an 19997 with a 5 speed.