i have a 97 f150 4.6 v8. I had a cel error po401. I replaced plugs , egr valve and solenoid, dpfe sensor, coil packs, and fianally pulled throttle body and ceaned egr ports that were completely clogged. I thought surely this was my problem but unfortunately it didn't help the truck. It still runs as rough as before. Maybe even a little worse. i would greatly appreciate any advice on this matter as I am at the end of my rope.

 

I got hell from a mechanic on therangerstation.com for this, but it's a viable option. I'd take it to a mechanic for a diagnosis (only) then fix it your self. Win win. They make money on the diagnosis and you figure out your problem. Sorry I have no tech info to share, but that's usually the rout I take when I'm at the end of my rope. Hope you figure it out man. Good luck!