Recently I put my car back to maf system. I know my old tune wasn’t going to be right on since I made changes to my motor since then. But it was darn close. My blm’s I got in line but my wideband is showing a leaner AFR throughout in closed loop. Running around 14.7-15.8. I would think it should be swinging at a lower AFR. I have a heated O2 in fact I had an extra new one and changed it. No change. Checked for leaks also. My aem wideband is about 4 years old. I’m running superrram, 219 cam , AFR 180 heads, 1.6 rockers, Hedman headers. Accel 30 lb injectors

 

Ok I’m starting to think I do have a vacuum leak. But in one of the worst spots. Lower part of the intake runners. Reason I think this, AFR changed their instructions. I don’t remember this being there about using rtv on the bottom of intake ports. Also remember one of the times I took my intake off and I was probably having a dumb moment at the time, but I do remember my intake ports being oily. My engine is definitely running lean checked a spark plug and looks fairly clean mostly. Not even tan.