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Tachometer slowly started to go about 2 or 3 weeks ago it would work for at initial start up but as soon as id drive out of the drve way it would quit, now it doesn't work at all but when i step on it, it bounces between 1500 and 4000 RPM is ths the sign of a faulty crank sensor? SES light is on and im wondering if this is contrbuting to the startng problem when it is cold, i was told by someone on the forum that it is most likly fuel/air related? any ideas?

[b]Could you add your year and model to your signature[/b] so we know what we are working with? Thanks.
My 93's tach is a feed off the ICM. Could be talking a bad connection there. Not sure at this point.

trf_ssei wrote:Tachometer slowly started to go about 2 or 3 weeks ago it would work for at initial start up but as soon as id drive out of the drve way it would quit, now it doesn't work at all but when i step on it, it bounces between 1500 and 4000 RPM is ths the sign of a faulty crank sensor? SES light is on and im wondering if this is contrbuting to the startng problem when it is cold, i was told by someone on the forum that it is most likly fuel/air related? any ideas?

Head to the nearest AutoZone and get them to read the code for you. If it's a crank sensor error, it has a discreate error code so you'll know it at that point.

When mine went bad, I had none of the symptoms you're describing. I would have a random "skip" or momentary loss of power for like half of a second maybe once every 30 minutes or so. All of this with no SES light. Then one day while in town it did it's skip deal and the light came on..... I immediately pulled into AZ and had them read the code. The guy there mentioned that normally you wont get a code on the crank sensor failing due to the fact that it usually fails pretty quickly and ends up leaving you stranded.

Replaced the sensor and all was well.

Well could a faulty icm cause my tach to crap out? with out any other symptoms. And could it also give me a miss fire? I thought at first that my coils might be faulty but thinking of the icm might not be giving full voltage to my primary windings.

I'd be inclined to think it might be dash/wiring/cluster related. IIRC the pcm needs to see the car running through the rpm in order for it to stay running and driving.