Hey guys I finally got everything together on my car just working on fixing minor coolant leak right now. But during my first test drive noticed that my afr are reading lean. I'm running open downpipe currently until I can get to the exhaust shop hopefully by the end of this week. My question being to you guys that have done this before, is it normal for the afr to be off due to atmospheric air coming up the downpipe and messing up the o2 sensors readings?

 

Yes

 

Okay thanks!