When I first took my 98 GMC Sierra in to check on what was causing an intermittent but really rough idle, they checked out quite a few things, but since nothing was conclusive, we decided to watch and wait. The fuel pump was a likely target, but since it didn't happen all the time, they didn't want to guess and hope that fixed it. This is why I love Five Star. They are not hijacking your wallet at every opportunity and they do excellent work. The following weekend the idle acted up a bit more than usual, so I made an appointment and they replaced the fuel pump at my request. I understood that this didn't guarantee a solution, but was highly likely the problem. So far so good, I'll just have to see if it occurs again. In any case, very happy with Five Star, highly recommended.