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.

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・Fair and transparent pricing

Get a quote

What others are asking

Q: i was driving my car on the freeway and it started to decelerate then it died could it be the map sensor or throttle position sens

Hello, thank you for writing in. The vehicle may be having issues with the throttle or its position sensor, the MAP senor, the mass airflow sensor, or the idle air control valve. With that being said, you can remove the...

Q: Car dying when put into gear

Your concern can be as simple as a broken/dry rotten hose that may be allowing too much air into the engine. The ignition system must be well-tuned and the alternator must be capable of charging the battery during vehicle operation....

Q: Steering vibration when at speed above 100km/hr

Hi Stanley, thanks for writing in. My first suggestion was to slow down, but then I saw you were talking about kilometers per hour and not miles. The shaking issue could be caused by all of the components that 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...
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...
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.