help with dodge 2.7 misfire?

Hello, I have a 2001 intrepid 2.7 with 82,000 miles. It had engine misfire cyliner 1 and 2. changed plugs and coil packs. same thing. changed cam sensor, crank sensor, and temp sensor. now it is getting worse and bad misfire at 2800 rpms. like it isn't getting gas. shop said bad ecm. bought one, (and they aren't cheap) they installed and programmed, same problem. now they said timing chain "stretched or jumped?" $1600 to replace. any ideas before I let them replace the timing chains? ( dont need negative comments as Ive heard these engines are bad) thank you