Tach sticking...I need some advice.

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Dec 23, 2011
New York,Ny,USA
is the tachometer directly affected by the crankshaft? I'm tying to figure out why after I accelerate the speedometer and the tachometer rise like they're supposed to, but if I take my foot off the gas and then reapply, if at that given time the tachometer happens to fall between the 1000 and 2000 rpm by the time I give it gas, it sometimes will stick within that range and won't budge unless I slow down even more or I give it alittle bit more gas with a quick step of the gas pedal, then it will bounce up and read the correct rpms. The engine seems not to be affected because the mph keep rising and engine seems to keep revs fine, although when the tach gets stuck there a feint noise coming from somewhere, But I can't tell where. when I give it gas until it gets unstuck then it functions fine. Does the tachometer have its own motor that operates it? because the Noise it makes is like something is getting stuck and trying to free itself. Also reading on the tachometer, receives impulses from different things in the car, What are the possible causes that my tachometer sticks like this and makes a feint noise. Is there anything in the tachometer mechanism that would make noise? Or is this a warning sign for an underlying problem. Also I haven't received any codes, I'd figure if it was something serious that had to do with the engine or transmission it would throw a code. I've researched this all over the net but I haven't found an answer because it doesn't seem like a common problem. Thanx for your time and replies. By the way I have a 2005 Grand Cherokee, 4.7 V8
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Sounds like either the tach is bad, or there is a loose wire going to it. Check for loose wires going to it, if they're good hook up another tach to the vehicle, and compare readings.
Sounds great, tell u the truth I'd rather the tach go than anything else on board that costs a considerable amount of money to rebuild or replace. It's not so much the tach sticking that has me concerned its the noise that's made when it sticks. I'd swear I can feel it on the gas pedal when It gets stuck and I give it gas. Someone I was speaking to told me the tach is a simple mechanism that wouldn't make any noise, but I'd hate for it to be something else. So for me to install another tach to compare I wud need to take down the instrument panel? Or is there an easier way. I'm not too mechanic savvy.
See if you can get a tach that mounts externally, basically two wires. Google tach/dwell meter, and you'll see what I'm talking about. They don't cost much, or you can have a local mechanic check for you.
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