Surge/low speed

Can anyone help with this problem? I have a 96 LHS 3.5, my son had the car and blew the water pump. The pump and timing belt was changed at a shop where most of the work has been done on the car since new. Since then the car has had a low speed surge. When coming to a rolling stop or a slight braking stop the engine surges and wants to stall, it is getting worse now. I have just changed out the air filter, wires, pcv, plugs and cleaned out the throtle bodies. I have also checked for leaks at the intake and everything is good. There are no trouble codes, just #12 for the battery disconnect. Can anyone suggest a cure for this?
Thank You in advance.
Ivan.

Ivan,
I think that our problems are related. I notice a slight surge after my engine cuts off for a moment as well. I don't know what to tell you, but I do know that I changed both my camshaft and crankshaft sensors with no benefit.

Best of luck. I'll let you know if I find anything that works. I'll be devoting a good part of the day tomorrow to trying a few things.