I have to pass emissions next week and I keep getting engine code p401 twice. I replaced egr, also drilled out the egr port in the intake manifold. Cleaned top and bottom and after of 45 min of driving it sets a code. But I just drove it 10 minutes ago, and no lights but my obd2 comp reads the egr code still. Please I've read tons online about this problem, but I don't know how to fix it I've torn that motor down 5 times, please help. I've heard a few say heat is the problem, others wiring is the problem, any advice will help.

it's 2002 Honda accord v6 200,000