hi there.
yep i had this happen too. i had never had any 3 beep alerts before that but it just kept going off every time i got the car up to 3900 RPMs or so. full jamming false alerts too
i also found that the led would flash seldom and/or very weakly also and sometimes it would just not power up again after i switched it off to stop a false alert until i lowered the engine RPMs or even turned it off altogether
after some time wondering and calling KMPH UK about this we came to the conclusion that it was the cars CANBUS system that was causing it and i switched over to the cigarette lighter as a power supply as that was easy enough to tap into and fortunately it was a "cleaner" source.
what type of car is yours? mine is a ford focus.
what did you earth the unit to? i used a bolt going into the bodywork on mine and a spare power supply that was behind the switch blank (that i mounted the kill switch on) on the centre column to power mine.
basically how i got mine to work in the end was by using the positive and negative wires on my cigarette lighter wiring to power the LPP directly. even using the body of my car as an earth was a no-go for some reason. unfortunately i have to remember to switch on and off my LPPs now as the cig lighter is not turned off by the ignition but it does work perfectly on that as its a more stable power source than i was previously using.
doing this also should be the end of your problem but if not then it would be possible that the damage has already been done to the system as it was in mine. it bought me some time but i had to get it replaced as the problem reocccurred unfortunately but since i hooked up the new one to a correct power supply from day one it has been working flawlessly
i hope this helps as i went through the same and its a real pain in the a$$

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V1 3.863 stealth hardwired with custom led remote display and remote mute switch
Laser Pro Park Dual up front
Laser Pro Park Dual on rear
Kustom Prolaser 2
Lti Marksman 20-20 w/speedscope
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http://www.youtube.com/user/corkguykev