Toyota Repair: Engine rattle for a while after turn-off, toyota corolla, fuel quality

Question
I have  a 89 Toyota corolla, five speed manual. It has 145,000 miles so far.  recently it has a couple of problems.

I can clearly turn the engine off. After turning the key  off, it will rattle for several seconds before completely off. Due to this, It failed the state-inspection.

Second problem is about acceleration.  I can not push gas pedal too much. Otherwise, it will lose power and rattle as if it were in a high gear with too low speed. It will be fine if it reach 60  mph.

Please give clues to fix the problems.  Thanks a lot.  

Answer
Suggest you make sure it has been tuned up.
plugs, air filter, check the wires etc,
The "run-on" could be caused by poor fuel quality, incorrect ignition timing, or high engine temp.
So, eliminate the obvious first. Tune it up, get fuel from a different station. Check to see if its running at proper engine temp.
Let me know what you find.

Mike