Q: My car rpm fluctuates slightly, during warm up and my temperature gauge also fluctuates intermittently.

asked by on

I bought this car used, has been running fine, but I just discovered recently after about 2 months of driving, that it doesn't maintain a steady rpm at times (not always). Rpm will go between 1200 and 800 during starting engine at different times. Also, when I engaged the transmission (especially in "R"), vibration is observed on the steering wheel. Though improves in the "D" shift position. However, after a few hours driving, these conditions are suppressed. The noticeable observation again, during this warmed up state is that I could see that the temp gauge needle fluctuates between coldest and normal working temperature of the engine (though never exceeds this level). This condition does not occur on every driving, say about 35% of all driving time.

My car has 239000 miles.
My car has an automatic transmission.

Hi, thanks for writing in. My first impression when you described the vibration is that you may have a bad motor mount. When you put the car in Drive or Reverse, the engine shifts slightly. If the rubber in the mounts is tired, it will transfer the engine vibration to the chassis of the car. As for the temperature gauge issue, it could be that your car is not warming up. If the thermostat was sometimes sticking open, it would prevent the engine from coming up to operating temperature. If the engine is not warming up, the injection system will remain in a cold running mode, producing a high idle. The best way to check if this is the case is to use a handheld non-contact thermometer on the radiator and the engine, you should be able to see weather the engine is up to temp, or if it may be an instrumentation issue. Replacing the thermostat is relatively inexpensive and is a good first step on temperature related issues. You can contact Your Mechanic and have the thermostat replaced at your convenience.

Was this answer helpful?
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
  1. Home
  2. Questions
  3. My car rpm fluctuates slightly, during warm up and my temperature gauge also fluctuates intermittently.

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: What is my vehicle’s load capacity?

Your vehicle’s load capacity is 905 pounds. The driver, passengers, luggage, and cargo, when combined, should not exceed 905 pounds.

Q: I just changed my oil the other day and it is already showing that i need more oil.

Hello There! This suggests you may have a leak resulting from a failing gasket somewhere in your engine. As you know, there are many different places in your motor that are sealed by gaskets. I would suggest narrowing this down...

Q: Why does my 199 Honda Civic act like it has a governor on it?

Hi there. This can be caused by a number of things, but if you are getting the codes that you mentioned then you may have a voltage supply issue. If you have this issue on both of these circuits it...

Related articles

Rules of the Road For Iowa Drivers
Driving on the roads requires knowledge of the rules, many of which are based on common sense and courtesy. However, even though you know the rules in...
What are the Car Pool Rules in Hawaii?
Hawaii is widely regarded as a land of vacation and relaxation, and as such, its scenic roads and routes are far better known than the state’s freeways. But, as with all...
P2103 OBD-II Trouble Code: Throttle Actuator Control Motor Circuit High
P2103 means there is a fault with the throttle actuator control motor circuit, likely due to a defective electrical component or part.