Sparking on the plugs & rev count up & down

?

Are you seeing sparks while the spark plugs are tight in the engine? If that is the case, then
you need new spark plug wires.

First step is always to check for stored fault codes in the ECM,

There are many things that can cause the idle to rev up & down. Do you feel the up & down
while driving at steady speeds 50 km/h, 80 km/h etc?

If it is only at Idle, look for broken vacuum hoses, dirty throttle body.

I need to know what type of engine is in your car to provide more specific information (3 letter
engine code).

Thomas