My 98SC 4.6 usually starts in the morning no problem. When the temp gets under 20 degrees it starts then stalls right out.It willnot run unless I feather the gas then it will run fine on its own.It willnot run untill I touch the petal. It only happens in cold weather under 20 degrees. I am goig to stop at Auto zone and see if they can scan it for codes. I have newer plugs and wires(Motorcraft)I appreciate any help. Thanks Bob

 

IAC, clean or replace, and clean the throttle body.