96 escort...need advise again please help

[Cavaturbo]

hi i already posted a thread recently about my engine light is flashing periodically and i already ordered the code reader from Ebay but it could take another 2-3 days for it to come. Right now i noticed that when i idle after warm up, the car feels like its shaking abit and sometime when i accelerate at very low rpm(when i release clutch) i could hear a small pinging sound. but i dont notice any lost of power. ( maybe becuase i never accelerate fast).

The car starts like normal. Also, every time i turn the engine off, i hear this "pop" sound kinda like a loud suspension squeak sound....any idea where is that sound comming from? Could this be the valve stem falling into the cylinder? are those the symptoms? im scare to drive now i dont want to damage it.

also, is it ok to keep on driving until the code reader is here ?