I have a 2001 GMC Sierra 4X4 with a 5.3 liter gasoline V-8 and about 99,000 miles. Recently, after driving for couple of hours at highway speed, the engine started "chugging" (suddenly loosing power, then surging), as if there was water in the gas. No warning lights came on, but the engine temperature gauge would swing rapidly to the low end and back as it chugged. I stopped, filled up the tank and added a bottle of STP water removal formula. The truck ran OK, for a while after that. For the next week, it drove fine around town.
I then took it on another road trip, and the chugging returned, again after a couple of hours, again with the swinging temperature gauge. I discovered that I could minimize the chugging by continuously speeding up and slowing down, and make it worse by engaging the cruise control. When I got back into city traffic, the symptoms disappeared, but it returned again after driving at constant speed for a couple of hours. On the way home, it got so bad I thought I wasn’t going to make it.
Two days latter, I took it to my local GMC dealer. The GMC dealer told me they plugged it into the computer and the computer said there was nothing wrong with it so there was nothing they could do. They had done all the service on it since it was new, and I had performed all scheduled maintenance. I had switched to full synthetic oil, but still changed it every 3000 miles.
I was convinced the problem must be either crud in my fuel tank or a faulty fuel pump, so I told them to clean out the fuel tank and replace the fuel pump, which they agreed to do. However, when they started it up (after it had sat idle for a few days), they called and told me they heard a rattling from the engine when they started it that indicated my engine was going bad, so they didn’t think it was worth going forward unless I wanted to replace the engine.
At this point, having gone from “absolutely nothing wrong†to “the engine is shot†in 24 hours, I lost faith in Mr. Goodwrench
I then took it on another road trip, and the chugging returned, again after a couple of hours, again with the swinging temperature gauge. I discovered that I could minimize the chugging by continuously speeding up and slowing down, and make it worse by engaging the cruise control. When I got back into city traffic, the symptoms disappeared, but it returned again after driving at constant speed for a couple of hours. On the way home, it got so bad I thought I wasn’t going to make it.
Two days latter, I took it to my local GMC dealer. The GMC dealer told me they plugged it into the computer and the computer said there was nothing wrong with it so there was nothing they could do. They had done all the service on it since it was new, and I had performed all scheduled maintenance. I had switched to full synthetic oil, but still changed it every 3000 miles.
I was convinced the problem must be either crud in my fuel tank or a faulty fuel pump, so I told them to clean out the fuel tank and replace the fuel pump, which they agreed to do. However, when they started it up (after it had sat idle for a few days), they called and told me they heard a rattling from the engine when they started it that indicated my engine was going bad, so they didn’t think it was worth going forward unless I wanted to replace the engine.
At this point, having gone from “absolutely nothing wrong†to “the engine is shot†in 24 hours, I lost faith in Mr. Goodwrench
Apr 6, 2010 at 2:35 PM