loss of engine power, warning lights were flashing on and off and my gauge needles were bouncing up and down, check engine light then came on and stayed on, throttle sensor problem maybe the cause in reduced power and cause malfuntion indicator lamps to appear, had to manually shift gears to try to get up speed. going up hills car slowed right down with the gas pedal to the floor still slowed down, no power to engine at all. It could be the fuel injectors.
The first thing to check is your battery. a weak battery can cause those problems. or the alternator not charging the battery.
When CEL turns on diagnostic codes are stored. Suggest to ask shop for those code numbers, and post here. Throttle sensor faults could possibly explain these symptoms. WW’s battery idea above is good place to start.
And you kept driving it… not a good thing.
Check the error codes stored in the engine computer… Check battery voltage as it sits now.