Intermittent faults on a car can be very frustrating. Often you may notice that something is not quite right but then when you take the car to the garage, they cannot replicate the fault. This can result in costly investigation costs and may mean you have to go without your car for a period of time whilst they complete their investigations.
Most cars are built with a type of on board computer that can be linked up to a diagnostic machine that will check the system for faults. This will then create a diagnostic report listing any fault codes it has found. The fault codes will refer to a problem with a specific part or function of the vehicle. Not all garages will be able to do a diagnostic on your car so it is worth checking with them first. Once you have the results of the diagnostic you can then make a decision as to what you want to do with the vehicle. If it is quite old, you may feel that it is not worth repairing and better to cut your losses.
A diagnostic can cost around £20-£40 depending on where you take it and you need to bear in mind that the diagnostic will not pick up everything that is wrong with the car just faults that have been recorded on the on-board computer.