Skip the auto shop - Our mechanics make house calls

Q: My engine is vibrating and making a knocking sound at idle, which grows intensely when I accelerate but it all goes away at times

asked by on

The car (lancer evolution X) was in my garage for almost a year. I had just changed my gear box (SST) serviced it and changed my tires. Everytime I turn on the car the entire thing vibrates violently with some knocking and even worse when at high acceleration/speed 75mph. However, there are times when I push the car drive fast or it all goes away for that entire day and the car feels as good as new. The next day the same thing happens. I found some oil stains on the engine and gearbox but engine and gearbox oil level are fine. There is barely any power loss gear shift is good no engine signs at all. No smokes from the exhaust and the oil cover is clean. Coolant liquid is thick green though as apposed to clear green? Coolant level and signs are also fine.

My car has 58000 miles.
My car has an automatic transmission.

A: This seems to be a torque converter issue. ...

This seems to be a torque converter issue. The bolts are probably loose between the converter and the flex plate. To get to the torque converter bolts, you will need to remove the starter from the engine and then you can access the converter bolts. Sometimes the flex plate could be cracked, making the same sounds and vibrations. The other thing that could cause an engine vibration that goes away at times is a loose heat shield on the exhaust system. Check the heat shield for any looseness and tighten it if necessary. If you need assistance, seek out a professional, such as one from YourMechanic, who can help you track down the source of the vibration in your vehicle.

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: Rattling sound from front axle.

A rattling sound from under the car could be a loose heat shield. But then again, it could be many other things. I suggest having a certified technician, such as one from YouMechanic, inspect your vehicle firsthand.

Q: Rattling Sound coming from underneath the car.

Hi there. Sounds like one of the heat shields on the exhaust system has broken a weld and is vibrating as the engine is revved up. Jack the vehicle up and put on jack stands. Go under the vehicle and...

Q: Maintenance issues

Hi there, thanks for writing in. I'd be happy to help. The gear shift assembly may be salvageable if there are no additional issues related to its functionality beyond it just being sticky from the soda. As for the A/C...

Related articles

How Do Power Car Windows Increase Passenger Safety?
Power windows are responsible for approximately 2,000 emergency room visits every year. When a power window closes, it exerts enough force to bruise or break bones, crush fingers, or restrict an airway. Though...
How Long Does a Distributor O Ring Last?
The distributor is part of the ignition system in your vehicle and its purpose is to route high voltage from the ignition coil to the spark plug. The spark plug then...
How Much Does a Mechanic Make in Vermont?
Automotive technician jobs in Vermont have an average mechanic salary of $37k, with some mechanics earning a salary of $53k.