I swear my 4runners tach has ADD.

It works fine under throttle, but when at idle it sometimes randomly drops to 0 RPM or just bounces around like crazy between 0 and 1000 RPM then settles back to normal for no reason and at totally random times. Once you start to accelerate it works fine, but at idle its hit or miss.

What could cause this, and how do i fix it?

Thanks!
Lamm

 

yep mine does that, but its usually when im cruseing down the interstate, all of a sudden it jumps up like 500 rpm, then back, then up.......... then back.....

i never paid it much mind

 

hey snap-on, do you notice it kicks in the same place on the interstate? and at a regular interval?

I found that a radar station on a backroad that actually climbed above the belt line of the dome would put me in the line of fire for the radar beam! my tach would jump at a regular interval (every 15 seconds or so?) Spooky for the people living over there. Getting microwaved at a regular interval just can't be good for ya.

 

Mine did it for a while, and then finally died. It's been reading 0 RPMs for a while now, haven't made the time to fix it....

 

Anything above about 145dB in bass send my tack and speedo into siezures....lol

 

BUMP, its driving me nuts.

Lamm

 

Mine is hyperactive...reads about double the actual value. I still haven't figured it out. I just shift by ear.

 

My new runner is an auto so its not a huge problem, but it just bothers me, a lot.

Lamm

 

Anytime I turn up the stereo (and I don't have a boom system or anything - I think due to the wiring) my speedometer bounces a little bit. Not a ton but enough to notice. If I turn it down it goes back to being the smooth speedometer it was. Weird.

 

Its strange because the only time any gauge acted up in my 92 was right after a 4' water crossing. And it had twice as many miles on it...

Lamm

 

So I am getting a vey similar problem with my tach running from 3k to 4k while holding a constant speed. I am thinking this is related to the sudden stumble that occurs randomly. Any ideas? Could it be tied in to the pick up on the distributor? Any solutions or comments out there?

JJ