anyone, please help me fix this problem
Chad,
Bad news, as far as I know, there is no fix. Other than buying a used factory tach/boost gauge out of another car, and hoping it works accurately. I'd just put an aftermarket one somewhere, that's what I'm going to do if I can ever decide on what I want to go with. I was told by a local "guru" (hope that term doesn't make his head get big, then he won't be able to get his helmet on!) that "the factory tach is like a rubber band, the more you stretch it, the looser it gets.....it's useless." Mine reads off more the higher it goes, I think at idle, 700-800rpm, it reads about 1100-1200, and it only gets worse the higher I go, like at 3000, on a WOT run, it reads all red, so about 6200+. If you find a fix, I'd love to hear it. BTW, if you've never pulled the dash apart to try and fix it yet. I wouldn't bother, the tach and boost gauge are one unit consisting of three circuit cards all soldered together with wires running from one to the other, in other words you can't just pull one out or just cut a wire, like a wire that JUST holds it together, they actually do something. Unless of course you either know what needs to be fixed, I checked mine and everything appears to be okay, nothing burnt or popped(cap), or you have a known good circuit card and are certain it's the only one that needs replacing, and not to mention something else is messed up on it, otherwise I'd just replace the whole unit. You can remove the boost/tach gauge if you want, it's just plugged into the dash harness, just might be hard to find or get to, may be shoved way up in the wiring. Good luck,
Scott