Skip the auto shop - Our mechanics make house calls

Q: I have a tapping noise coming from left side of motor on top while pressing the gas on cold starts.

asked by on

When I push the gas to accelerate in the morning or during a cold start period I hear a tapping noice only when I push the gas. Has been going on for about 2 months now. Oils never been ran low and I use 2nd grade gas. It idels fine with no taps at all or even revving the engine while in park it still doesn't tap. But if I put it in gear and take off it'll start tapping while I'm pressing the gas.

My car has 197234 miles.
My car has an automatic transmission.

A: Hello. The most common cause of this noise ...

Hello. The most common cause of this noise in your vehicle is a leaking exhaust manifold. It is common for the bolts on the rear of the manifold to break, causing a small leak. Most of the time you will hear it in park, but if the leak is very small you will not hear it until you start driving which puts a larger load on the engine. If the exhaust manifold is fine then it may be caused by a lifter that is collapsing. I would usually pull the valve cover off to inspect the rocker arms for looseness. If it is loose then it may need a lifter. If you plan on having the vehicle looked at as a certified mechanic can come to your home or office to diagnose the source of the sound.

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: Heater blowing lukewarm air. Had thermostat and gasket changed plus heater core back flushed. No change.

The heater is reliant on the engine temperature getting up to and maintaining normal operating temperature. Once this is verified then you can check both heater hoses in and out of heater core with blower on low speed and heater...

Q: I'm not sure what to do or what I need to have fixed or replaced

Hello. If there is a ticking or knocking noise coming from the top of the engine, then it may have the damage that you mentioned. If the noise is not very loud, then it may be normal as these engines...

Q: Power issues like battery or computer

The symptoms you are describing are those of an alternator failure. The alternator is supposed to charge the battery at just above 14 volts consistently. If the voltage drops down to 12 volts, the alternator is not charging the battery....

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...
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...
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...