Your symptoms sound typical for O2 sensors, but could also be EGR related. Changing O2 sensors on your SVT won't be that hard. You'll want to jack/jack-stand the car to get at the downstream sensors which are underneath on the exhaust. Pull the coil pack to get the the upstream sensor on the rear cyl. bank. Try a search on O2 sensor and you'll have lots of advice. The sensor socket is about $8 but you can get a loaner from autozone.
