I was reading the other posts, some of them, pertaining to this issue. I've had my truck in the shop several times and it has them stumped. No codes show up.

When the truck is off idle, driving about 5-20 mph, and there is no load, it surges, not misses, but surges like it wants to leap forward, then dies off, then leaps forward. It's been narrowed down to the EGR circuit, but they aren't sure what. If the vacuum line is removed from the EGR valve and plugged, this issue goes away. Eventually the check engine light comes on and they read a code (forget what) that had to do with the EGR. Pretty obvious why, it's unplugged, I plug the vacuum line back in, and the problem comes back, and eventually the check engine will go out.

Can anyone steer me to a previous post or shed some light as to how to diagnose those?

I don't have a code reader, but do have a vacuum pump and extra guages.

Kraig

 

have you checked all of your vacum lines for leaks?

 

Yep, so has the shop.