Hi, after my check engine light came on in my '98 F-150, I took it to AutoZone to have them check the code. They informed me it was the ERG valve and that I should try cleaning it or replacing it if that didn't work.
Problem is, I don't know where the ERG valve is since I know nothing about engines. I would hate to have to pay someone just to have them clean the valve out if it was something so simple.
I have reset the computer twice and the light eventually comes back on. I haven't been experiencing any other problems with the engine.
I too suffered through this problem with code P0401. I changed the ERG Valve and the PDFE switch and it did not fix it. The light came back on in a few miles, but I finally fixed my 98 4.6L F150 with 112,000 miles by cleaning the ERG ports. The ports I'm speaking of can only be accessed my removing the throttle body ELBOW off the top of the intake manifold. It's an elbow that connects most of the vacuum lines including the ERG Valve. I got a lot of carbon out of their using a drill bit by HAND and that fixed it. There is a simple test to tell you if the ports are clear.
Remove the vacuum line from the ERG Valve and cap the hose. Start the engine and let it idle. Then apply vacuum (outside source) to the ERG Valve. The engine will stumble or stall if the ports are clear. If the engine continues to idle without change the ports are blocked and need to be cleaned. I cleaned mine in about an hour it's not that big of a deal on the 4.6L
I wonder if they used the old throttle body on your new engine.
The old engine had 167K miles on it before it finally went. I had purchased it from my father who put many miles on it driving it back and forth from Upstate NY and Indiana. He in turn had purchased it from someone who had put high miles on it.
I am not sure if they used the old throttle body or not.
Since I know next to nothing about engines, I might just try to find someone to do it for me. I am kind of intimidated by this sort of thing!