If a scanner was used, it should flag which cylinder had a miss fire and shoot a code. As far as a limp home mode, not sure, if you were running on five cylinders, might not get it over 40.
Either way with a code you can figure out what went wrong, just a though anything can go wrong with electronics and not be the shops fault. Could be a coil or plug, or plug wire that just decided to go.
Either way with a code you can figure out what went wrong, just a though anything can go wrong with electronics and not be the shops fault. Could be a coil or plug, or plug wire that just decided to go.