Erratic rpm display and trans flaring (ffs does it ever stop?!)

Ill be quick since im on a phone.
Nailed it (when i shouldnt of, stupid me) and then the tacho started going haywire. Now it does it randomly but the engine is still fine, i.e not doing the 5000-10000rpm its indicating. Also having some bad flares now. I know rpm comes from the ptu but is there anything else i can check, i have parts a plently just CANNOT believe i fix one thing and another stuffs up. Selling the car too so i need it fixed!! Any advice from the pros??

Thanks in advance.

I have to admit I got scared and thought fuck it someone might respond. popped the bonnet and started with the basics, seems the 6 pin plug on the PTU had become dislodged ever so slightly, so I've pushed it in good, and took it for a short drive, tacho is fine thus far. I'm sure that's all it was.

Sorry for being hasty and starting another thread.