2004 Pontiac Aztek over revving tachometer over eighty degrees outside

[greg johnson]

Every summer if my Aztek has been running awhile and it is over eighty degrees outside the tach will start running five thousand more revolutions than usual. Anyone else have this problem?

 

[melsg5]

5,000 or 500?? Big difference.
Hot air has less Oxygen then cool air , computer may be compensating

 

[greg johnson]

Unfortunately 5K. Was hoping is was a common issue but appears not to be.
How about the key getting stuck in the ignition and having to use the emergency release to remove from car.

 

[melsg5]

I assume you mean only a wrong tach reading, not the engine 5k+ ?
Try some lock cylinder lubricant

______________________________

 

[G-416247]

Unfortunately the engine actually revs up more.
The key problem is an electronic one where the switch will not fully come back to the proper position to release the key properly. One notch short. So have to use the emergency release under the steering column to get it back to the final spot to easily remove the original key.

 

[melsg5]

You may have carbon build up in the throttle body, try cleaning.
The key lock mechanism would have to be disassembled to determine the cause of the problem.

 

[G-309846]

You were right that it was 500 extra revs not 5K. I was not thinking! Thanks.

 

[G-611851]

Turns out the old transmission is the problem.

______________________________

 

[melsg5]

Has it totally failed?
Have you ever changed the fluid and filter?

 

[G-210534]

Not totally failed but apparently the torque converter is not working correctly. Changed the fluid and filter back around 110k miles. Occasional hard shifts and sometimes reverse stops. Diagnostics say turbine/input shaft speed sensor out of range.

 

[melsg5]

Since I dont know how many miles are on it now 110k doesnt tell me anything. Try a bottle of Lucas transmission additive.