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

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: My car is getting overheated, replaced the water pump, but coolant is still running out.. After the car warms a lil..

A thermostat is a good first step with overheating issues, usually because it's inexpensive and easy to replace. So it's always good to eliminate that as a possibility, but I think you may have more problems then that. I presume...

Q: Lights out on dash

Hello, thank you for writing in. The dashboard lights have a dimmer switch that you need to double check is not turned down. The switch can also fail causing this issue. If equipped, you can test the switch for power...

Q: Idle is running high when driven. I put it in neutral and it idles at 2300 rpms. Just had a cold air intake put in and throttle cleaned

Hi there. Assuming your vehicle has ETC (electronic throttle control), "drive-by-wire" problems can develop when cleaning is performed. Manually opening the throttle plate may have affected the close position. An idle relearn performed with a capable scanner may resolve the...

Related articles

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 P0052 code means This code is seen when the Engine Control Module (ECM) tries to control the...
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...
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...