B4000 idles rough, RPM's drop when at a stop

I have a 1997 Mazda B-4000 4x4. It starts and runs good for the most part, but about 50% of the time when I start it up, or stop to idle, the RPM's want to drop - sometimes down to 700-800 and sounds like it wants to stall. Also when cruising at a steady speed, (usually a low rpm 45-50 mph) I can sometimes feel the truck jerking or surging. I don't see the rpm needle move or jump when it does this. This may be a separate problem or the same issue. I cleaned my MAF, and IAC. My EGR looks a little worn, but would the EGR cause problems like this? Please help!