Hi everyone i've got some questions about my engine. So I recently got a Audi A3 1.6 liter 74kw 101hp 4 door from year 2000 and it's been great so far except recently when it suddently starts to hesitate when i give it some gas. It is a car made into a tractor in Sweden so I as a 15 year old can drive it at 30Kmph and it's speed limited on the ignition coil with a device from the company Loh Electronics and the one I have is called H Regg or Loh Electronics version H and it limits revvs and speed so it shuts of the spark when i reach 30kmph and the car shakes quite violently but thats not the problem here. So for an example im going any speed under 30 like 20kmph and when I give it some gas it just doesnt have power and the engine hesitates and rattles. The car got about 20000 miles well european miles idk what the difference in impereal and metric miles is. I just replaced the fuel filter, oil filter and the oil. It got a new sport air intake with one of those sporty air filters. I might need to replace the sparkplugs or the ignition coils but i have no idea what's causing the hesitations when giving it gas and its not always it happens its more when the engine has been running for a little while almost no hesitation when its cold but i dont anyways give it that much gas when its cold. Hmm i just cant figure out why it hesitates i can send a video of it if anyone wants. And also when it hesitates if i press the throttle more the speedometer needle sometimes jumps up a little

I meant to say its a single ignition coil with the wires going to each of the 4 sparkplugs