Erratic tachometer reading

[Jeremy Parrett]

My tachometer is reading erratically. I have read about a 'fix' for this involving diodes or capacitors to remove the stray RF that is causing the tachometer to over read.
Can someone tell me specifically what the values of this fix are ?
2000 Marquis Amethyst C12.

[Grant Stanton]

Hi Jeremy all I can tell you about this problem is on my 97 Marquis when my tach started acting up it was because the alternator was on its way out and when the alternator did quit so did the tach. After replacing the Alternator it worked fine.

[Jeremy Parrett]

Hello Grant,
 I hope that is not the case but I will get the alternator checked.   Thanks.