Recently bought a mk1 Leon cupra r 132k 52 plate when the maf sensor is plugged it it ticks over fine but just splutters when I drive. When I unplug it it tick over like crap revving it’s self from 500rpm to 1500rpm but it drives fine when you get going. Got a new sensor and it’s stoll doing the same? Any ideas what it could be? Car has a bad exhaust leak from behind the engine that’s getting fixed Next week. Could this be the problem?