Trunk Wiring problems of the 2001 Chevrolet Impala

I waited for recall parts (ignition and oil leak) and had them completed 4/13/16. On 4/22/16 my car started smoking coming off the freeway, I pulled over and the engine stalled, people yelled to get out it was on fire. The fire started in front of engine and proceeded thru engine compartment burning all plastics and wiring. Dealership says I'm responsible for the damage since I didn't have full insurance coverage. How can that be, my car was fine until they worked on it. Dealership was also very rude and condescending. I hope all Chevrolet dealers aren't the same. I gave dealership 7 days to resolve the problem, however they basically told me no one can help me. I almost burned up in this vehicle.

Bought my chevy 2001 Impala may 2010 at 114,000 miles. A week later the check engine light came on for the mass air flow sensor. Car ran fine, changed the maf in February 2011 as the car began to chug at stop lights. A week later the car stalled on the way home after about an hour of driving. Had spark plugs, filters, fluids, tps sensor (twice), crank shaft sensor and ignition module changed. Car is now chugging, stales out, after stalling the turn signals do not work for a while and has trouble climbing tall hills (does not excelerate). The check engine light comes on occasionally and it reads the tps sensor is bad. Checked the wires near the tps sensor and maf sensor noting when touching wires the idle of the car increases. Come to find out there was a compartment fire before I had bought the car and it appears some wires were spliced. In process to change the wiring harness. Unsure if this will fix the problems.

Rear of car caught fire. Occurred in my employer's parking lot at 2121 hudson avenue, kalamazoo, michigan. The third brake light area. Vehicle parked & unoccupied.