Temperature of extruder tanks as soon as I extrude

Title says its all I have messed with PID auto tune all day with relativley the same results. It will go down to about 172 then return to normal even with a quick extruder turn any ideas? Here is the pronterface graph.....

Idling with nothing moving......
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With extruder turning.....
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I also just noticed it does this when any of the motors turn on x,y,z could it be a power issue?

Very well could be. Check your +12v when your motors turn on at the board and see if it drops significantly (5+ volts)

Yes actually I measured the Vin on my melzi with the motors on it 7 volts when off about 12..... I am suprised I thought that my power supply can't provide 12 volts over 1 motor and 1 heater. I had heard good things about these power supplies, perhaps I am doing something wrong?

[www.ebay.com]

One of two things either you ordered the wrong one or you have a bad one did you get the 30 amp version and does it say 30 A on the power supply. Could also be you have a short somewhere in the motor wiring but it is probably a bad power supply

It's only 20 amps but it still should be enough for a hotend and ONE motor I guess its defective?