Skip the auto shop - Our mechanics make house calls

Q: Engine won't rev past 2500 rpm?

asked by on

I've checked for leaks, found none, cleaned & replaced MAS sensor, same problem. Replaced throttle body, no change. Replaced, throttle motor relay, no change. What is next?

My car has 175000 miles.
My car has an automatic transmission.

A: Hi, thanks for writing in. You may have bee...

Hi, thanks for writing in. You may have been on the right track with the throttle body. I went down this road with an XK that was going into limp-home mode and not allowing the engine to rev up. In that case, the throttle body was the answer, but it didn’t solve the problem until I disconnected the battery for about thirty seconds, then hooked it back up. The car performs a kind of re-boot where the ECU and the throttle body have a little handshake (you can hear it when you turn on the switch making a little zip,zip sound) and the ECU learns the values of the new throttle body.

Disconnecting the battery is no small thing, you will also have to re-initialize a number of other features, radio code, window motors, possibly the door locks, but doing this re-boot may put you back in business.

Here at YourMechanic, we can have a technician come to your home or office to inspect and diagnose this issue for you, and make or suggest the necessary repairs.

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: Oil pan is leaking

Hello. Thank you for writing in. Unfortunately the oil pan is a pain to get to on most vehicles. There really isn't another way to access the pan. High performance compact vehicles can be even more crowded making access to...

Q: If the computer was calibrated wrong, can that damage the computer.

A computer calibration will not damage the computer unless the update failed. If it failed then the vehicle would not started right after the calibration was done. Then all that would need to be done too redo the calibration. ...

Q: Throttle pedal doesn't react after being replaced on a Renault Clio

They all sell French cars here in Texas. I don't have experience with them anymore but most modern cars, when you change throttles on them, they have to be reprogramed to work. Even Fords and Chevies are like that. So...

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...
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...