I have a 2002 Buick Lesabre 3.8 L. that I just acquired 2 days ago. The vehicle will not go over 35 mph. I hear a faint whistle coming from somewhere. All coil packs are working. I recently repaired a vacuum leak to the evap purge solenoid and the fuel pressure regulator. There appeared to be a missing hose that attaches to the vacuume hose leading from the break booster into the back of the plastic intake manifold and the car dies when I plug the hole while car is running but stays running if I plug it before starting the car. I just replaced the fuel filter. I hear the fuel pump kick on and the car is getting fule pressure at the front of the car. New air filter. Throttle body was just cleaned. Has no strong rotten egg smell to me but my sinuses are clogged. The wife says she smells something but can't describe it. Does have a code for oxygen sensor on bank 1 sensor 2 low voltage. But I didn't think that could cause the car to not go past 35 mph. Also has new MAF sensor. A friend said he dont think the cat is clogged but he isn't a professional and I don't think he preformed Any tests to determine this. Also, not sure if it's connected but the fuel gauge dont read correctly. While under the hood if I give it gas it sort of sounds a bit like a muffled helicopter. And shakes a bit under hard acceleration while trying to pick up speed. Also, it will pull a hill just fine but extremely slow. And has plenty of air coming from end of tailpipe but is really hot after just a couple minutes of idle. Any idea how to fix the issue of not getting past 35 mph?