# What's up with the RPMs



## jamesd3rd (Jun 10, 2004)

I noticed something odd with my '93 Altima. A couple of times when some one in front of stopped short on the freeway which resulted in me locking up my wheels, it somehow affected my acceleration. My tach would start showing higher RPMs when traveling at about the same rate of speed as before the lock up incident.

In other words say I was traveling with the flow of traffic (roughly [email protected] RPMs) before the lockup incident. Afterwards, in order to reach the same speed, my tach would show about 4000RPMs.

Can anyone explain this? It's as if the transmission is not shifting properly. I have an automatic transmission.

The car is in need of some work. The speedometer seldom works unless the car has been sitting outside in the sun. It seems to stick which causes the 'Check Engine' light to come on. When the speedometer unsticks, the light goes out. It's been going on for so long that it's pretty much stuck all the time. My mechanic claims it's just a matter of replacing the speed sensor. I had the sensors checked a while ago for code faults and nothing turned up. I was told at that time it was the speedometer header and it needed to be replaced. Something that was on the order of $300 for a used one.

I don't know if that is related to my RPM problem though.


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## KA24Tech (Feb 2, 2004)

It sounds like a bad speed sensor in the trans and it would only show up if you don't turn off the ignition when the light comes on because it is registering as a temporary code. Speak to your local Nissan dealer to order one or check with one of the Nissan Forums sponsor dealers.

Troy


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## jamesd3rd (Jun 10, 2004)

Ok that addresses the speedometer issue. Any ideas what's going with my RPMs? The times this happened I was on my to work. When I left to home, everything was back to normal. So this RPM things seems to revert back to normal after a time. How much time I'm uncertain about.

I wasn't aware that locking up the wheels from hard or sudden braking would have impact on RPMs.


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## KA24Tech (Feb 2, 2004)

Let me do some research and then get back to you for possible causes on that one.

Troy


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