Not sure if anyone else notices that the RPMs may be off slightly during a sudden take off, and hard driving... I feel as though the RPMs are "behind the motor" slightly. I'm curious to take it to GM and have them use a TEC 2 to check this out. (Wonder if the TEC 2 would be off too)

 

It's a fairly common problem, there's a couple other threads about it on here. Mine hits the limiter showing only 6000 rpm's in first, and then makes it to 6500 in all the other gears. Just cheap and slow gauges.

 

it's an electric guage... it's all jacked up

i think they should replace everyone's electric guages with mechanical ones for free... when my gas guage gives readings that are off as far as 1/8-1/4 of a tank at times, the rpm guage jumps around like it's nobody's business and the boost guage... god only knows what is actually going on with that thing.

 

factory tachs are not the most accurate---among most cars.

 

Older stock Tachs aren't that bad like my 1993 Z24. But newer cars like my 2002 Camaro and my Cobalt suck.

On newer cars there is no direct signal to the tach, the signal is first used by the computer then sent to the gauge. It's pretty common to see a shift light set at 5800rpms to light up when the tach is reading 5100rpm in a LS1 F-Body.

 

the tach in the cobalts and the redline moves to slow for as fast as the motor revs


the final drive gear and 1st gear as pretty low , and with the 2.0 and s/c it revs faster than the tach can keep up

 

Lucky for me I dont look at the rpm gauge when I am hard driving. I cant really tell how it lags, but the all do at least a tiny bit. I prefer to just listen and feel the car. Stock gauges have always been a bit off in this bang for buck price range. Overhauling and replacing your gauge cluster is a tedious, but not really hard process if you have clear instructions. If its that important, check out Auto Meter.

Sounds like you need a shift light?

 

how do you get to redline then?
its not easy to tell 5700rpms from 6300 rpms

 

Its definitely sounds like an annoying issue. Manufacturers have been building automobiles for 100 years now, yet they still can't design an accurate tachometer?? Just doesn't make sense.

It sounds like something that could be easily corrected with a dealer reflash. I suppose GM just needs to come up wth that reflash first though, which for some reason isn't happening too fast...