Runs but no power when taking off

Don't know what the problem is. Anybody knows Appreciate any help given

an old trick we used to do is advance the ignition timing 2 degrees to raise fuel economy and get a little more power out of the engine. As vehicles age the vibration dampener where the timing marks are would sometimes slip and would retard timing. Your exhaust maybe getting restricted causing back pressure restricting engine output. This would restrict power through out the RPM ranges. To check this, find an old oxygen sensor and gut it out so you have just the threaded part and hex piece with a hole clean through. Get a short piece of 1/4" steel tubing (I.E. brake line) and braise or weld the pipe into the hole making sure you seal all the way around the pipe and O2 sensor or you may find something ready made. Get a vacuum gauge and some vacuum hose that will fit over the 1/4" tubing and long enough to snake the vacuum gauge out the hood and slide it under your drivers wiper blade or tape it to the windshield so some one else can watch the gauge. remove the oxygen sensor closest to the engine and install your gauge setup. drive your vehicle around while observing the gauge. these Gauges read vacuum and lower pressures. It should see 1# or less. if over this, your exhaust is restricted and should be looked at.It could be a partially plugged catalytic converter, muffler or a restricted pipe. Good hunting and have fun!