Engine misfire?

[Bams]

Hey all, left my expy at my parents for a simple fix and they let it sit for two months, apparently didn't touch it once. Now it seems like the engine is misfiring? The service engine soon light is on, and it flashes over 1500 rpm or 30 mph. I have 0 power, especially uphill, and it stalls in reverse. Engine shakes the whole car at 40 mph or greater than 1/4 throttle. Is this a misfire or could it be something else

 

[Yupster Dog]

There is no need to start multiple threads about the same thing.
The one thread in 1st Gen is sufficient enough