1997 Jeep Cherokee Country

Sometimes when I start my Jeep and take off the speedometer will bounce from my actual speed to 100 and back a couple of times and start jerking very hard. After a minute or so it will clear up and run fine. It especially does it in very cold weather even if I let it warm up for 10 or 15 minutes. I’ve wiggled the 3 plugs connected to the ECM and it won’t do it anymore for a few weeks but when it gets cold again it will start doing it again.