for my skoda fabia i have changed the spark plugs but i think those were wrong, bought from amazon. those are for LPG CNG cars instead of petrol. since then my car is sluggish. is this the reason car is not accelerating.
Cause and effect… could very well be a reason. Swap them to the correct plug. don’t depend on Amazon to tell you if it is the right spark plug, their search engine for auto parts is pretty poor - as you found!
Yes. Almost always the best plugs are the ones specified by the carmaker when the car was new. Anything else is an experiment and quite possibly a mistake.
If it protrudes too far into the combustion chamber in an interference engine, the physical damage caused to the piston crown can be very serious. If the plug used is of a higher heat range, then you will experince starting difficulties and higher fuel compsumption.
Doesn’t matter if it is an interference engine. Can happen to ANY engine, interference or not. “Interference engine” is a description of valve clearance if the timing belt or chain breaks.
Heat range has nothing to do with how hot the spark is, that’s controlled by the gap, heat range is how fast/slow a spark plug dissipates heat.