My replica car with a GM 5.3L engine was running rough, smoking a bit and smelled like the engine was burning rich. Doug initially diagnosed a fuel regulator issue and addressed that; however, the engine still ran rough. Doug further diagnosed that three fuel injectors were not delivering fuel to their cylinders. He attempted to flush them, but this was not successful. So, he sourced three replacement injectors and installed them. He advised me to fill the tank and gave me a fuel additive to further clean the fuel injectors. The engine now runs smoothly with good power. Throughout the repair, Doug kept me informed of his findings and provided me cost estimates for.the additional work needed. All troubleshooting and repairs were completed in less than two days. I requested Doug to keep the vehicle sheltered if held overnight. This was provided. I was very pleased that the necessary diagnostics, troubleshooting and repairs were completed competently and in a timely manner.