Temperature gauge

When i am driving my temperature gauge in the dash reads "normal" but when i accelerate or increase the rpms the gauge quickly moves down to cooler and jumps around very quickly from cool to normal and back and forth, but only when the rpms are higher, like above 3.5. whats goin on?

Test the battery and charging system. Make sure the battery posts and clamps are clean and in good condition. Could be the bad connection occurs as the engine moves under acceleration. Does the temp gauge do the same when the trans is in neutral?

Yeah man, it sounds your battery might be bad or your not runnung enough power to your engine.