I have a 1994 5.0. I pulled the codes this morning and one of the codes was 172 running lean. How can I remedy that? I just checked vacuum leaks and fuel pressure everything seems to be working normally I don’t have an egr or an air injection pump. I had my egr plugged up by a plate with a gausket that I cut out of a piece of aluminum (it seems to seal just fine) . But I had the egr plug plugged by an eliminator plug from eBay could that be a problem or am I looking in the wrong spot.