I have a 95 psd that has been acting up the past few days. It runs really bad (rpms rising and dropping) and the throttle doesn't respond when it's running like this. As long as I drive it normal (no lead foot) it runs fine but if I run it with a lead foot the rpms go nuts and if I push throttle nothing happens. Sometimes it will start right back up and run fine but sometimes it won't start and if it does it runs rough and pours white smoke. When it runs good, there is no white smoke at all. Maybe connections under valve covers? The check engine light hasn't came on at all...

 

have it scanned, it sounds like injectors but I had the same problem without the white smoke and it was just a loose connection under the valve cover.

 

get it scanned like he suggest. my 95 did that one time, then ran great for 400 miles, next day it wouldn't stay running. injector harness was shot.