My son owns a 09 DTS with about 82 K miles. He, we, and shops have screwed around with this POS for six months trying to get it to run. He drove it to work one night, ran fine. Next morning wouldn't start. Shop had it for two weeks got it to run poorly then nothing. We have replaced fuel pump, crank w/ Delphi (twice), cam, knock sensors, ecm (Delphi) (Flashmasters programmed) scan tool pulled bad crank sensor and harness trouble, we replaced and scan tool doesn't link, nothing what a s**tbox! Last resort tomorrow. If this shop can't fix he's gonna dump it. What possibly can the problem be?