2002 Volkswagen Jetta engine problems

I have been going to board walk volkswagen dealer in richardson and rusty wallace volkswagen in garland, texas for my repair for my car for more than 8 times. The car is still not repaired and I am very frustrated. The problem is that when I start my car, it shakes really bad I would have to warm it up for 5 minutes. Sometimes the car dies while I am driving. I wrote a complaint letter to the rusty wallace because I purchased my vehicle there and the service manager (dan turk) seems to be avoiding my phone calls.

2 times I had to replace a faulty 02 sensor 1st time engine temp sensor. Rear left light burned out 3-4 times within 80 000km. Said it's easier to replace then find the problem at dealership. Have done oil consumption tests 1 litre of oil per 3161km. Saying that this normal. This dealership have recommended flushing the engine. Changing the grade of oil. Do not drive in rush hour traffic. Most of the consumption occurs on the highway and not in traffic. Change the oil instead of 8000 km at 5000km???