Had a bad misfire problem with my 1999 Chevy truck. Chevy dealer told me it was probably a bad fuel injector. Took it here and the guys found it was just a cracked spark plug. Problem fixed. Diagnostic cost a lil over $100 but way cheaper than replacing a fuel injector , and the diagnostic tests checked fuel pressure , compression, etc. . Was worth it , saved me lots of money. The price of the testing was worth it.