My check engine light stays on but has no rough running or stalling. What could be the problem?

Hundreds of things. Literally hundreds. The CEL will light when any fault is detected by the OBDII system. Begin with gas cap. Make sure it's tight and the rubber seal is not folded, crimped or deteriorated, that is the #1 reason a CEL will light, a small leak in EVAP. Then go to a large parts house and sk them to do an OBDII scan. Some do it , some charge, some don't do it regardless. But don't pay, go to another parts house. Then, some of the guys know what they are doing, others not so much. Electrical parts can not be returned, even if never installed. Write down thew codes, will be a alpha-numeric, P for Power train. Bring the codes back here, in a new question (this thread will get lost in shuffle) .....so we will know.

Have check engine light codes read at a parts store like auto zone they will read it for free. Most likely a oxygen sensor but still best to get it checked out before it starts running rough.

Good morning f-b338

The only reason I went in to the part about 'go someplace else'is the AutoZone in nearest me will not do a scan. I then bought my own scanner. (NOT from them)

Wzup FordNut

Did not know that thought all auto zone stores read the codes.

Ported this earlier but it did not go through. Wzup FordNut I liked the the post you give saying you are to the rescue and showed that guy like he was running. Good stuff. LOL