Has newly rebuilt engine from block up, duff ideal , engine light on

What is your question?

My, 2004 ford focus has a newly rebuilt engine from block up. Had checkers put auto ,( plug iunder dash) and it said scenser's, it's one of the denver's. It has a duff ideal, doesn't have asuch power as it should have and the engine light is on. I need the secenser, " witch", one is the reason I need.to have that fixed. Doesn't leak, or anything. Just needs the right secenser, how much will that cost?

What makes this problem better or worse?

It doesn't matter, warm or cold

How long has your 2004 Ford Focus had this problem?

Few days