2000 3.9 Van hard to start w/ cold engine

I have a 2000 Ram Van with a 3.9 engine that has been sitting for about a year and a half. I thought it had a blown head gasket but I put a new radiator
in it and now it no longer gets hot!!! The only problem is it is hard to start on a cold engine. It kind of sputters like it wants to start but doesn't until I start
pumping the accelerator real hard. It runs good the rest of the day, even after sitting a long while. I gave it a good tuneup before it broke down.
wires, plugs,ect.

Thanks,
Ricky Newman

Change the 2-wire (not the 1-wire) temperature sending unit next to the t-stat housing.