I'm getting a check engine light. The codes I pull from memory are a paired 33 and 41. I clear the memory. Later, another light and another 33, 41 pair.

I've recently replaced the EVP (motorcraft) and the EVR. I have good vacuum to the EGR (which also holds vacuum). The 02 sensor was recently checked out as ok.

Any ideas on this pair?

 

well according to my haynes manual:
33:EGR valve opening not detected
41:HEGO sensor circuit indicates system lean
41:No HEGO switching detected.
The double 41's are kinda confusing but i hope this helps