Why is tach bouncing?

[grlaneriejr]

Hey guys, a question.
I just changed my plugs, cleaned my O2 sensor, cleaned my temp sensor, and adjusted my valves. Now my car runs much better.
I have another problem, though. Now my tach is bouncing all over the place, also my MPG guage. Why is this doing this? It didn't before.

Does anyone have any ideas?

[MattE30]

Could be the SI batteries, or bad wiring, among other things. I suggest chaning the SI batteries first, and if that doesn't work, maybe replace the tach unit.

[grlaneriejr]

I don't know. I let the car sit for about 3 hrs and now it's fine. weird, huh?

[bimmerphile]

Loose ground on the back of the cluster?


Broken wire in the SI board?


Those are my guesses.

[grlaneriejr]

okay, i'll check both of those out next weekend.

thanks

[qimis]

mine started like that, it went crazy

and couple days later, it died ....

[McGyver]

I don't know. I let the car sit for about 3 hrs and now it's fine. weird, huh?

i've been having that problem since i bought my car a year ago. i have the motrometer display and i thought that it would start to bounce to a higher rpm when it was hot cuz after it sat for a while it would be steady again. well i have been driving it everyday for the past month and no jumping and now i have the problem again today. when i rev it high it will seem to catch up and read acurate again until the rpms drop. i also had my ecometer bounce down and my mph bounce down for a few minutes one day. is this the problem you're having and did anything fix it?