I own a 1992 GMC Sierra 1500 V8 5.7 L. Three weeks ago, I had trouble starting my car. I took it to AutoZone and had the battery tested; they said it was bad and replaced it with a new one. Almost immediately I noticed I was having acceleration and shifting issues. I took it to a friend who said since it was an older vehicle, it was having to "relearn" how to drive. When the problem persisted and became worse, I decided to follow-up with an auto shop and have them inspect my vehicle along with my routine oil change.

The mechanic told me I needed a tune-up and a new fuel pump, sending unit, and strainer; he went ahead and put a new filter in because he said he couldn't test the fuel pump without it. I asked him for repair estimates ($1,300), paid for the oil change and new filter, and decided to look around for comparable prices. Found out a family friend could fix it if I bought the parts (he used to be a mechanic), so I had him perform the work...after which, I could almost immediately tell a difference in the way she started up and ran like a champ.

I drove it for a week, and she ran perfectly fine until last Friday when I was trying to accelerate from a stop light. All of a sudden my truck died in the middle of the road. I had electrical power (radio, windows, etc.), but could not get the thing to start for the life of me. So I called AAA and had them tow it to the place that had initially done my oil change (I'm fairly new to the area and didn't know where else to take it; in hindsight, probably should've taken it somewhere else instead).

The guy called me the following Saturday and asked what happened. I told him I had replaced everything that needed replaced, but now it won't start. He said they'd take a look Monday and let me know. Fast forward to today, and I still have yet to hear anything from him. I finally called on Wednesday for an update, and he said that he had "tested" my fuel pump and he thinks someone installed it wrong or its a faulty part.

My question is this though: Can he "test" my fuel pump if 1) I have a locking gas cap and he doesn't have the key, and 2) my truck hasn't moved from the spot it was towed to? I just have a hard time believing that he'* been unable to perform any work on my car whatsoever in the week it'* been there (particularly if it is just the fuel pump), and I feel like he'* more than likely brushing me off since I neglected to get it repaired at his shop the first time.

Any advice or help would be greatly appreciated... Thanks.

an easy test though not very definitive would be to take the air filter off and crank the engine and watch the spray pattern in the throttle body, should have a nice strong smooth cones shooting from both injectors. if you dont have that could be a loose or corroded wire in the pump harness. also pretty common is where the ground for the tank connects to the frame is poor or loose. alot of people just disconnect it when you take the tank down and dont clean it, but it needs to be shiny and tight. the only way you can own a old vehicle is if you work on it yourself, old stuff is hard work and adding 200% to the parts is pretty standard for the types of shops that dont want the hassle. even honest shops are going to be more because it takes twice as long to get things apart and sometimes you end up running new lines because whatever is broke when you try to do things under there