AUTO REPAIR TIP-WHAT IS A DIAGNOSTIC?  There is actually no such thing.  Diagnosis or diagnosing the particular problem with your car takes a system scan and then a careful analysis and testing of parts that are likely to be at fault. Much of the public believes that a MAGICAL COMPUTER exsists that tells us what is wrong with cars.  This is not true.  I think this came about from the face that back in the 1980's huge complicated analizers "scopes" were commonplace in shops to test engine electrical systems.  As impressive looking as those were they are as antique as a model A compared to what our laptop size testers can do now.  Liikewise the vehicles that we work on are vastly more complicated then they were then. Although we have many pieces of test equipment that help us solve problems, the "crystal ball" that can tells everything has not yet been invented.  painstaking testing, wire by wire, component by component, coupled with a mechanic's brain filled with technical understanding and years of experienced is required to correctly diagnose the thousands of problems that your car could develope. Some of the most difficult tasks facing a mechanic are correctly analizing customer complaints, then properly testing a vehicle's  various systems to arrive at an accurate diagnosis.  Anyone can guess, but to properly troubleshhot a modern car takes time and understanding ofhow all this stuff works. For testing the myriad of complex and interrelated systems that make a car work, it is worth paying for a smart technician.  Today's cars shange every year as designers develope more and more complicated vehicles.  The Apollo space-craft that went to the moon had much less onboard computing power then your car.  I don't think NASA would have wanted your neighbors brother-in-law poking around under the hood of their rockets just because he was a mechanic in 1962.  Don't let him mess with your modern car.  You will regret it.  Get help from a professional shop with a good reputation like TOYOPROS. Many customers complain to us that some "bargin" shop didn't fix the car right.  Bargain priced shops and chains like K-mart, Wal-mart, Pep Boys, Midas, etc. are not usually such a great deal. We are willing to guarantee the results of our diagnosis, If it's isn't fixed, you don't pay.