hey guys I'm new and i brought my ke30 about 5 weeks ago. all is going sweet but just recently the speedo tends to be a bit tempramental.

it reads the rong speeds all the time as in ill be in 3rd gear doing 150 WTF..

 

and quick fixes.

check the speedo cables attached correctly first. I have a tacho in my car and because i have swapped gear ratios and diff ratios and tyres and wheels my speedo is all out of whack, but I've driven behind my other half doing 100 and mine will be reading 110 and the tacho will sit on around 4k, so I just go by the tacho.

You could always do a swap or figure out by what percentage your speedo is out (i.e. mine's around 10%, so at 60kmh zone i should be doing 66). Or get an aftermarket one.

I know a friend who uses their GPS nav to tell them what speed they're going.

Sounds more than just a minor variation in speed reading due to tyres etc. Is it elec or mech?

 

If it's doing erratic things like crazy speed changes then it sounds like you've got some speedo drive problems.