Posting this info for others to learn by my mistakes and what ultimately was my solution.
After trying to gravity feed (and manually blow vinegar) thru the hose, and not having much luck, I found the wife turned on the hot water and not the cold in the tub. So the only open line was going through the hot water tank.
In her defense, the caps on the knobs were reversed. I never noticed this as H has always been on the left and don't really look at how they are marked. This explains her other complaint about not having hot water sometimes. lol
Anyway, the vinegar did nothing. I ended up having to take the city connection completely apart. I found the backflow assembly had come apart and the spring assembly was not doing it's job in not restricting the inflow. I suspect the good pressure we have in combination with poor/cheap design of the backflow device caused it to come apart. Once I reassembled and put everything back together I now have decent flow again. I really should replace the backflow assembly but I would have to cut the caulk from the exterior, dissemble/reassemble and recaulk it back onto the exterior. Not sure how much they charge for the part either. I might pick one up and have it ready for the next time as I suspect it will happen again...