I have 1976 RR silver shadow automatic. The car was broke for 4 months and now I have to pass the smog check and want to drive with the car. The mechanic has been working on for a while( changed air intake tube, EGR valves etc.) Last week the car start and I drove many miles and middle of the freeway. It stopped. So, mechanic fixed and car is driving again few miles and it stopped again. Now the car starts works perfectly and has a lot of power but as soon as I put in drive position it stops. Car starts perfectly but in drive position dies automatically. What is the problem?