Thanks Stuart, that's certainly what I was hoping for for. That car has the sports exhaust as well though correct? Would that play into it?

Not really sure what to try next. I don't think that an exhaust leak would explain my results (and I have no reason to suspect I have one). The car had modest mileage when I got it with full AM service and no issues at all. It has never thrown codes (aside from what I note above that were incidental with the tune) or had any issues whatsoever since I acquired it.

I'm still planning to repeat the dyno in dry cool conditions in a month or two and will post results then. At that pt, I'll be able to run both version of the tune back to back also.

 

Theoretically yes, by a very small amount but not enough difference to really pick up on.

I would look at a couple of things. Check your fuses. I can't remember the number off the top of my head, but the actuator which advances the camshafts is also responsible for the O2 sensors. I have come across cat installations where an O2 wire was shorted and it blew the fuse, meaning that the car never advanced the cam position.

I would also consider getting a scan tool (I'm using an Actron tool on a Mustang protocol - picks 112 data streams) and checking the O2 sensor response/signals. As the O2 sensors reach the end of their lives and start producing less reliable data, it can affect the fuel trim.

 

Good thoughts, thanks. Do you have a link to a vendor for the Actron tool?