Skip the auto shop - Our mechanics make house calls

Q: Temperature gauge erratic/ rpm erratic

asked by on

Temp gauge goes to 260 then rpm would Rise and drop.also noticed pcm/elm Seems hot

My car has 111000 miles.
My car has an automatic transmission.

A: Most likely this is a problem with the inst...

Most likely this is a problem with the instrument cluster. Even so, I would make sure your vehicle isn’t actually overheating. The best method for doing this is with the use of a infrared temperature gun. They aren’t cheap, but there isn’t another way to be absolutely sure. You can feel the upper radiator hose to see if the thermostat is open. The hose will be hot if the stat is working properly.

The tachometer and the temperature gauge rely on the instrument cluster module for the proper information to display. GM clusters are common failure items, so I am certainly leaning this way. I am not sure what you mean by the PCM/ELM seams hot. Modules will often become warm when the car is running. Although, if these problems begin only when the PCM gets up to operating temperature, it may have a problem. Although, PCM are rare to fail, so I would do every test I could imagine before replacing it.

I recommend having this looked at by a certified technician, such as one from YourMechanic, as one of our mobile technicians can come diagnose a potential overheating issue and help you pinpoint the issue with your gauges.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: Engine overheating

Hi there. I would strongly recommend pressure testing the cooling system to ensure your vehicle does not have any leaks or pressure drops. Also, be sure to bleed the cooling system thoroughly. It is imperative to bleed the cooling system...

Q: My gas gauge is doing a funny little dance.

The fuel pumps are all inclusive on what they call a fuel module or assembly. These modules include a float (quite like the float on your toilet) that tells the computer and your dashboard where the fuel level is at....

Q: Knocking when engine warms up

When the engine is cold, the viscosity of the oil is higher along with the internal bearing clearances in the engine. As the engine warms both the viscosity of the oil lowers and the engine bearing clearances can increase dropping...

Related articles

How Long Does a Distributor O Ring Last?
The distributor is part of the ignition system in your vehicle and its purpose is to route high voltage from the ignition coil to the spark plug. The spark plug then...
P0240 OBD-II Trouble Code: Turbocharger Boost Sensor B Circuit Range/Performance
P0240 code definition Turbocharger Boost Sensor B Circuit Range/Performance What the P0240 code means P0240 is an OBD-II generic code triggered when the Engine Control Module (ECM) detects the intake boost...
P2428 OBD-II Trouble Code: Exhaust Gas Temperature Too High Bank 1
P2428 code definition A P2428 trouble code signifies that the PCM has detected a problem in the exhaust gas temperature sensor circuit in bank 1, which subsequently contains the number one...