I’m a poor seminary student near Boston MA (Wenham) looking for a solution for my 2002 Tahoe. I love this truck very much because it fits me perfectly since I’m 6’7 and build like a linebacker. I’m having trouble with the power coming out of the car. Some days it drives very smooth and I have all the power in the world however sometimes it begins to feel very sluggish as if its really struggling to move. There is a faint whining come from under the hood, almost sounds similar to what a turbo on a car would sound like, but obviously there’s none of that garbage on my truck. Sometimes its very audible and sometimes its not so it might just be a squeaky belt. I’m looking for a viable solution that wouldn’t be too hard for myself to solve, I’m fairly handy. just to help eliminate I’ve already had a 100,000 mile tune up on the truck, its currently at 116K, I had the U-joints replaced a year ago, and a fuel pump three years ago. I recently added an oil-honey additive to solve a clicking that was happening when I first turned on the car in the cold, and I usually add a fuel additive (STP or Gum-out) every 1500-3000 miles. And if it makes any difference I’m about due for an oil change. Thanks all!
Is the check engine light on? If so, then there are error codes stored in the computer. Many auto parts stores will read those for FREE! If you have then read, write down the exact code(s) and post them. the format is “P0123”
If the check engine light is not on, then you start with the most basic stuff. “Tune up” doesn’t really mean anything specific these days. So if you have the 100K work invoice pull it out and provide the specifics. Your symptoms can come from lots of different things. Spark plugs and wires and checking fuel pressure are the places to start. (Many auto parts stores also have “loaner tool” programs and many include fuel pressure gauges).
Also check your transmission fluid. It should be at the correct level and be nice and red and not smell burned. (Has the transmission pan ever been dropped for a filter replacement?).
Investigate any codes that turn on the check engine light. If the fuel filter was not replaced as part of the fuel pump job you might want to see to that.
If you do not use a top tier fuel you may be facing another fuel pump replacement.
Mechanics can drive the truck with a fuel pressure gauge attached to see if the fuel pressure drops off when the power loss occurs to confirm this problem.
Thank you for the advice, I have had the sparkplugs replaced and the check engine light is not on. transmission fluid seems to be ok, the color is good, it seemed to be slightly dark.