Q: RPM fluctuates when shifting into gear

asked by on

Have a 2000 honda civic with a d15b and a cvt transmission, whenever I change from reverse or drive from park the rpm drops low to almost stall and then goes back up to normal other than that the emission smell high and smoke misty smoke. It drive great other than that

My car has 288000 miles.
My car has an automatic transmission.

This may be a sign of a faulty MAP sensor as the vehicle responds adversely to a load put on the motor (i.e. putting it in gear, turning on AC or engaging the brakes). The Manifold Absolute Pressure (MAP) sensor senses engine load and generates a signal that is proportional to the amount of vacuum in the intake manifold. The engine computer then uses this information to adjust ignition timing and fuel enrichment. When the engine is working hard, intake vacuum drops as the throttle opens wide. The engine takes in more air, which requires more fuel to keep the air/fuel ratio in balance. When the computer reads a heavy load signal from the MAP sensor, it adjusts the fuel mixture to slightly more rich than normal so the engine can produce more power. The computer will then retard (back off) ignition timing slightly to prevent detonation that can damage the engine and decrease performance. This may also be caused by other closely related components such as a dirty or failing mass air-flow sensor, a faulty throttle position sensor or potentially a vacuum leak. I would recommend having an expert from YourMechanic come to your location to diagnose and inspect your vehicle.

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. RPM fluctuates when shifting into gear

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: Hard shifting from 1st to 2nd

Hi there. The problem with your transmission is the 1 to 2 shift accumulator has either a broken spring or a split o-ring on the piston. You can replace this very easily. Drop the pan and gasket. If you just...

Q: Brake pedal has very little resistance

From what you've described, I'd advise you to not drive the vehicle and get the brakes bled out. It's possible that you still have a brake fluid leak in this case. I'd suggest having this looked at by a...

Q: Can I swap a non vtec engine to a vtec engine?

The two engines are different and you would not have correct wiring and computer for this different engine. Would recommend finding the correct motor.

Related articles

What Causes Hoses to Leak?
While the largest part of your engine is mechanical, hydraulics plays a significant role. You’ll find fluids at work in a number of different areas. Your car's fluids include: Engine oil Transmission...
P0052 OBD-II Trouble Code: HO2S Heater Control Circuit High (Bank 2 Sensor 1)
P0052 code definition HO2S Heater Control Circuit High (Bank 2 Sensor 1) What the...
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...