Well heres the deal, the speedometer needle jumps all over the place deviating from the actual speed of the car by +/- 5-7mph. It keeps doing that until I hit 85mph, after that it becomes steady. Could this be the speedometer cable or the instrument cluster itself? Any help would be greatly appreciated.

Thanks
Sohaib

 

I noticed in your sig that you have IS wheels and a sizable drop on the suspension. Those 2 factors could most likely account for the inaccuracy of your RPM gauge (and perhaps the speedometer and odometer as well). It's been mentioned many times before that a wheel and suspension upgrade could force those gauges to be out of calibration. Check with the tire/wheel shop where you got your IS wheels installed and see what can be done for recalibration.

FYI, Tire Rack has a good article covering "Speedometer Accuracy".

 

Lexusk8 has a good point, if you left the IS 215/45-17 size tires on, the speedo will be a bit off. If you put 215/50-17 on, this size matches up almost exactly with stock diameter, so that shouldn't be a problem. However, over/undersized tire diameter with respect to stock should only cause it to read low/high compared to normal, and wouldn't explain wild fluctuations. I'd check the speedo cable.

 

FYI, there IS NO cable. (never seen one...... anyway)

digital sensor on the wheel, one wire up to the dash, processor chip in the cluster.

 

Thanks for the replies guys, I checked and the tyire size is indeed 215 45 17. But the guy at tire rack told me that this would be the size that would fit. But the problem with the speedometer needle is not that of a calibration, but the fact that the needle jumps around all over the place. When I put the wheel and tires on, for the first 1000miles it worked fine and then it started doing these wierd things. My maxima had a similar problem where the speed kept fluctuating but then I changed the instrument cluster on it and it was fine. I am just wondering if in the case of an ES300 if it is the cluster or the speed sensor (I didn't know our cars did not have cables!). Any help would be reatly appreciated.

Thanks
Sohaib