We recently had the timing chains along with numerous other components replaced on our 2012 RRS with the 5.0L SC V8 engine by a highly recommended indy shop in Colorado. Since then it's been back several times for codes and restricted performance issues. The one code that keeps coming up is a P0107 code. Manifold absolute pressure/barometric sensor low input. The repair shop said they replaced it with a "known good sensor" which I'm not sure means used or an aftermarket one. Anyway it spent a month or more there and now they're recommending we replace the engine wiring harness at a cost of $6500!!! We've already spent more than $15k on the repairs so far. Is there something they might be overlooking and could fix this problem? It's very frustrating because before it went in for repairs it ran fine besides the timing chain noise and now it seems it's one problem after another. Any advice would be helpful.