I have a 2000 Ford tauras with the 3.0 DOHC I bought it with 173000 miles on it . New plugs wires ohm test coil all fine runs good..sits for two days same problem but no codes.Why?

Duh.. I bought the car 4 weeks ago when I got it at idle it sputtered alot and i had to feather the throttle when driving to get good acceleration. As I said I changed plugs wires and ohm tested the coils found them all to be good. It ran fine after that except for starting it cold. The idle would race to about 1200-1500 rpm for about 1 min then would drop to 900-1000 . It did sputter a little about every 30-45 seconds but had no problems with acceleration. After it was warm I could start it without it racing at all.I drove it Friday to work with no problems. It was parked and not run all weekend, and when I started it this morning it not only sputtered bad at idle it also had no acceleration. I tried giving it throttle at idle and it would not go over 4000 rpm. Could this be a fuel problem? I don't know if this would matter but the temp here went from upper 20s and dry to upper 40s and damp..any help would be greatly appreciated.

Also I should state that the car throws no codes