[Schwarzeritter]

1. See if wifey used a card and see if you can't find a recipt with a price that can give clue to potentially what fuel was used.

2. One of my facilitys is in a desert " lol " and so such problems are not un common. You really need to go and check the belts and ignition system, etc.

3. Now I have not used a SW unit. But depending on how SW programmed specific parameters in conjunction this could easily
be a issue, if you added items " performance parts "
post SW install the settings would not be ideal.

If that's even the problem, inspect the injectors, oxygen sensors and metering devices.

I have more suggestions but primary systems should be checked. But pings are no bueno! Good luck!

PM me if you want.