If all you have for tuning is an fmu/fpr all you need is a wideband and a few minutes of street tuning since all you only have one variable you can really adjust. I would highly suggest looking for another form of engine management though that can adapt for weather changes. If you current set-up is getting that far out of wack to be throwing cel’s due to temperature variations you are bound to blow things up if you skew the tune richer/leaner from where you are to account for either warmer/colder air temps and then the weather goes the opposite direction.