Skip the auto shop - Our mechanics make house calls

Q: Engine is running horrible with stalling and noises under load.

asked by on

recently it suddenly started running really badly. I'll list my observations.

-Loud, low pitched roar as the engine speed increases -rough idle, revs jumping all over the place, sometimes stalling, especially if air con is on. -metallic (tappet) noise when under load, higher engine vibration, worse than usual acceleration. -Often misfires, especially in the first minutes of operation.

This group of symptons used to appear periodically in the past, but would eventually disappear a few minutes after appearing, as suddenly as they appeared. I'm more worried because it has been 3 days with these conditions, and it has not improved. I'd really like to get to the bottom of this because it doesnt seem like the usual wear and tear that an old engine like mine displays, due to the sudden onset of the bad running, and that the issue usually resolved itself in a matter of minutes. Engine is a 4A-F (carbed) with 324,000km on it.

My car has 200000 miles.
My car has a manual transmission.

A: Hi and thanks for contacting Your Mechanic....

Hi and thanks for contacting Your Mechanic. As for the engine misfiring and having an issue with the rough idle, there could be a vacuum leak on the engine. Check all of the vacuum hoses and the intake to see if its sealed. Also, check the brake booster to see if its leaking vacuum. For the loud noise, there could be an exhaust leak or the engine could have a worn bearing in the engine. There could be a rod bearing that has too much clearance and is causing the tapping noise under a load. Also the engine could be vibrating due to an ignition problem. Check the distributor, plug wires, and spark plugs for corrosion deposits and heat burns. Check your carburetor for any adjustments that could be out. If you have traveled to a higher or lower evaluation, then the carburetor will need to be adjusted for the altitude. This will help with the stalling of the vehicle. If you need further assistance with your vehicle, then seek out a professional, such as one from Your Mechanic, to help you with your engine misfiring having a tapping noise under heavy acceleration.

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・Save up to 30%

Get a quote

What others are asking

Q: Barometric Pressure Sensor Error Code

The next step would be to do a proper full pinpoint test indication in the troubleshooting charts for the code that you got. This test will check the wiring, connections, ECM connections and the ECM itself. If you do not...

Q: My car stalls and my injectors stop spraying 1998 Nissan Sentra

Hello. If your car is stalling and it stops spraying fuel then most of the time this is caused by a failure in the crank position sensor. This is a common issue on this vehicle. When it fails the computer...

Q: Car loses power

This may be a sign of a dirty or failing mass air flow sensor. The mass air flow sensor is a unit in the intake system that monitors air intake as it is mixed with fuel prior to being injected...

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...
How to Renew Your Car Registration in Oklahoma(DELETED)
Having your car registered with the Oklahoma Tax Commission is an important part of driving legally in this state. You will need to do this within 30 days of moving to Oklahoma...
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...