Most likely problem is the CPS crankshaft position sensor; most off the self auto parts store CPS will have a very short life. This is one part you want to replace with a Bosch sensor. Go to FCP Euro or partsgeek and get the OEM Bosch replacement. On the Limited there is a heat shield very near where you will be working, not sure how that works on the SRT6. You can remove that shield; there is no need to replace it.