98 G30 Surges along when step on gas

1998 G30 Chevy Van: Hope someone can tell me whats this? Here we go,,, Start the van no problem, idles nice, good responce.Put it in gear and it goes 10ft and surges foward, it goes up and down in Rpm but just surges along. Put it back in Park Or N and engines again has good up and down rpm. Can even hold brake and step on gas and it feels like it will brake torque and as soon as you go into D and step on gas it surges again10 to 12 Ft foward up and down. What next folks? Thanks for reading.

I'm new to the forum, this is my second post I would like to help though. I would need to know if the check engine light illuminates. Off the top of my head, vacuum leak comes to mind and EGR stuck open which acts like a big vacuum leak similarly faulty PCV. Another possibility that is not uncommon and is consistent with a surge only when accellerating from a start is a dirty MAF sensor, which may not illuminate the check engine light if the conttamination is border line.