Skip the auto shop - Our mechanics make house calls

Q: Changed heads. Engine runs great until I put it in gear, then I have no power from transmission, shifts hard, and breaks are hard.

asked by on

Checked all vacuum lines no leaks

My car has 180000 miles.
My car has an automatic transmission.

A: Hey there. Given that you performed a fair ...

Hey there. Given that you performed a fair amount of engine work and have no doubts with the battery out of the car, it is possible that the throttle position sensor and engine management have lost their "pairing" values and an "idling re-learn routine" is in order. After disconnecting the battery, wait 10 minutes, reconnect battery, start engine, put in gear Drive for 1 minute (idling), put in Reverse 1 minute (idling), and drive moderately for 5-10 minutes. After that, idle re-learn should be complete.

It is also possible that given your mileage, the throttle position sensor is simply failing. The TPS affects both engine power and shift quality since the transmission takes signals from it for upshifting.

The "stiff brake pedal" sounds like the vacuum line to the brake booster was not properly re-connected, or one of the vacuum/vent valves in the brake booster has failed.

If you would like to have this all scoped out for you, a certified technician from YourMechanic can come to your car’s location to diagnose the loss of power, shifting problem, and hard brakes in person so that this can be corrected.

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: Hazards and turn signals not working

Hi There, your turn signals and hazard lights share a lot of the same wiring so both of them quitting together is pretty common. You will want to check your bulbs first. I have seen bulbs blow at the same...

Q: The abs block does not let fluid to the rear brake lines

Hello, when bleeding brake with an ABS system you will need a scan tool to open the passages in the ABS module. This is part of the brake bleeding process. If you'd like, a certified Your Mechanic Technician can...

Q: Changed brakes and rotors now the emergency brakes is squeaking when driving. What could be wrong?

Hey there. As you may know, your emergency brake is operated and controlled by a separate drum brake assembly located behind the rear disc brakes. The emergency brake is operated by a drum brake set up with brake shoes that...

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...
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.