RPM surge cold start

[Fretzy]

On a cold start as its idling high the RPMs surge and you can hear it in the engine as it does it but its minimal and tapers off as soon as the high idle drops below 1000 rpm and is not there when the engines hot. Scanner showed MAF sensor and ive cleaned it but there is also a small knick in the yellow wire going into the MAF plug which i have taped (still surging afterwards) no CEL or anything else showing. Thanks for any suggestions 👍