Code p0401

What is your question?

I have a 2001 Toyota Camry. My check engine light came on and threw this code. My car runs great. Plenty of power and now problems at a idle. I pulled the her valve and cleaned it. Not much carbon build up. Check engine light back on with the same code. With the car running fine does that help indicate what the problem might be?

What makes this problem better or worse?

Nothing

How long has your 2001 Toyota Camry had this problem?

It was my mom's car and it's been like that for awhile.