Engine Performance problem
2005 Mercury Monterey 6 cyl Front Wheel Drive Automatic 80000 miles
I recently had a code on my van p0401. With that code I went ahead and cleaned the Egr valve with carb cleaner and reset the code by disconnecting the neg. Battery cable. I put egr valve back on and put neg. Battery cable back on. The code has been gone for 2 weeks now. But now I am getting horrible gas mileage. I have not figured it out manually yet, but by the computer or miles till empty goes way faster. What is going on? Thanks.