Used car become choice because its have cheap price, but problem always facing on this kind of cars. As my experience used car have many problems especially for very old cars. The problem are not only on the physical or body of car, but in insight of car part also have problem. The physical of old car you can see the problem like the body or housing of lamp and some of other parts that you can try to run at the time. But the insight problem always make a problem like the cabling system on the car. Many of cable are not used anymore and still stick on your car and sometime still have electric current flows on the cable and this can make your cable system is overload and hot.
Leg parts of the car obviously to be replaced, like bolt join and tire. Your car must be reset to get a normal car and can run smoothly. All cable should be checked and replaced if needed and look like irregular connection. All of censors must be check how they work and may reroute again. On this work you need electrician that already expert on cables changing. If any wrong connection on car cables and be dangerous because it can be short connection and can burn your car immediately. Beside only corrected on car engine. Other important think beside your engine car is break system should be worked perfectly, if needed all the part that joint the break system should be changed with new part. Disk brake and drum brake may already exhaust , oil tube usually have corrode and should changed also. All part should be recheck include of power steering system, because this is very important when the car run fast, the problem on power steering can make accident.
Fuel consume of old car usually not efficient as new car like new build by this year, because its already modified by the engineers about how they can consume efficient, it very difficult to modified this in order car can consume fuel as little as possible to run the car.