Rev Counter going mad?
Turbo Mini Forums

Whenever i was driving along and booted it, revs above 4k, more noticeable in 3rd or 4th, i would hear a loud kind of electrical popping sound. AT this point the rev counter would go kinda wavy, not reading any particular number, but roundabout 4ish, or roundabout 5ish, like it was drunk. I had the boost pressure sensor on a mnual switch and was only running 4 psi unregulated at this point. Could it be backfire through the carb?

i need more ideas folks!