ok guys my first question i am posting on here.(please dont be a grammar ****) lol.
anyways i have a 96 honda civic lx with the d16y7 engine in it with an auto tranny. my tachometer appears not to work. what it does is when the key is in the off position it sits directly at the 6'oclock position, when the key is on it is quick to move to a random place without the engine even started but usually it cogs out under the 0 at the stopper. then after about 5 minutes of driving it will move to the redline area between the 6-8k rpm range and will not move from there. very seldom i will notice that the needle will move to the correct rpm and work like it should, hasnt happened in months though, then after a couple minutes it will wonder off to wherever it wants again, typically to the redline area, i have checked rigorously for loose connections or a break in the wire and that is non existent. and i do notice during a cold start after the first few minutes of driving it will bog down almost to no power and when i give it gas it quickly picks up and quits acting like its going to die. that leads me to believe that maybe my tach has a problem inside of it but it is not throwing any codes or nothing of the like to do with it. i had a cracked manifold so i put the header on because it made my o2 sensor burn out so i put the secondary o2 sensor in the primaries spot just so it can read the ratios and that is the only reason my cel is on because i have the secondary o2 sensor wire just sitting not hooked up. if you need any more specifics i can tell you anything you need, i am not limited on tools, just experience so please any help would be appreciated and maybe this can be a knowledgeable post for people to learn from. here is a video of it running and what i have looked at so far.

 

Check your connections,i har one do that and it turned out to be a groung issue.

 

kk i will try that

 

if its not a connection then i would just swap in a used tach.