heating issues with e3d and sprinter

hey all, got an e3d v5 and am using it with stock 100k thermistor with sprinter software
the issue im having is when i set my hot end to temp it jumps to approx 250, then works its way back down to below 150, i can sometimes set it back to temp but just keeps going high, then dropping out, colin from makerfarm is being a real help but doesnt know what to do with sprinter settings
ive attached my sprinter.pde file wondering if anyone can help? thanks!

We need config.h

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Waitaki 3D Printer

Are you sure that the thermistor isn't loose in the E3D? Maybe a defective thermistor?????

Thermistor is pulling accurate temps, tried with my stock jhead and having same issue so I'm guessing its in the code. I'm away from my pc so I can't get to me configuration.h file to post

Just wondering if anyone else has seen it