yeah the 5th gear thing is because the auto gate blocker for reverse isnt kicking in so you go too far over. If you find the right spot it will go in, after all gearboxes are mechanical so nothing electrical can prevent 5th engagement.
Make sure you dont try for 6th or you'll hit reverse :shock:
Once the speedo resumes the gate blocker will kick in again and and your 5th will be accessable again.
I recently had a speedo converter problem . The CEL would come on after about 2 miles in the morning. funny thing was the car would Vtec then , before the light come on it wouldn't Vtec. The speedo was bouncing around , on/off 150mph then 0Mph then it would settle at 0Mph.
I ordered the first converter a speedm8 programmable but this was bouncing about a bit so I telephoned the company and they sent me another one. (I had to pay again, but he said they would refund it when I sent the other one back £65)
My original one was located near the gearbox but the new one was fitted behind the dash. It works perfect and the car feels more responsive.
This happens every now and then on my car. Wierdly when its really cold outside.
I do not get the engine mangament light but the speedo does not work and it does not go into 5th gear.
Usually turning off/on again fixes. Probably is a fault with the KPM/MPH convertor