i had the air and egr deleted when i had my computer tuned. i never blocked off the egr i just left it hooked up. before the tune i was getting the p0400 code for the egr. could this be causeing me to lose power? im wondering cause i dynoed again last night after the tune and the power was 4rwhp less then last time. the only thing i changed was the opti, plugs. wires, and the tune. any help would be great. also the A/F looked good

 

anyone?

 

I would suspect you could get a 4hp variance from back to back pulls. Doesn't sound significant, IMO.