2000 Cougar, several problems

Well, this car never stop making troubles. It's a 2.5L V6. Now I have these problems:

1. There's a harsh noise coming from under the hood at the driver side when I release the gas paddle in cold days. Occasionally the car would stall after that. The noise is immediately gone when I push the gas paddle.

2. Check engine light on with code P401. I know it's with the EGR system. I had the EGR sensor changed. The engine light was gone for a week, then come back.

3. The electric power is unstable, making the dash board light and all other lights dim in and out and low speed. No problem at above 55 mph. This happened after I changed my battery.

I really appreciate if anyone can advise. Thanks.

Needs a DPFE sensor and Ford Products are known for these going bad.

Needs a DPFE sensor and Ford Products are known for these going bad.

What I meant by "EGR sensor" is indeed the DPFE sensor.

I would suggest cleaning the exhaust passeges to and from the actual EGR valve. Sometimes this requires removing the throttle body to gain access. I had one of these for two months, I dumped it ASAP! Nothing but problems and headaches. Good luck

Also make sure the hoses to the DPFE are a not clogged and are a snug fit with no pinching.