By October 31, 2012 0 Comments Read More →

Rattling and Tapping In Engine

After my husband changed spark plugs and wires (he crossed the wires the first time and then corrected them) I have been hearing a rattling/clattering noise when I decelerate.

It also make a taping noise when idling, the noise does seem to become louder at times rather the engine is cold or hot. Very rare. It does not make this noise when accelerating, Do you have any Ideas. Please help Thank you


Why hello there,

The very first thing I would do is check the engine oil level. The oil level could be low and need to be topped off. The tapping noise you hear is probably caused by the lifters at the top of the engine not getting adequate lubrication…..which could damage them.

You can also buy a can of Marvel Mystery Oil at your local auto parts store. This is can is added to your engine oil and is designed to quiet noisy lifters. You might be able to get the guys at the auto parts store to listen to your noise and determine if the lifters are the culprit.

If the oil level is ok and the lifters are not the culprit, you might have a problem with the catalytic converter. I have heard many converters that have come apart internally clatter and rattle and sound like pop corn popping when the engine is at idle, on start ups or on deceleration.

The catalytic converter is located under the vehicle…probably on the passenger side, and is part of the exhaust system. If you can get your head/ears under the vehicle (with the engine running and car in PARK of course) see if you can tell if the noise is coming from the converter.

I don’t think this is caused by your husband replacing the spark plugs and wires. If the engine runs bad, the check engine light is ON (and was not on prior to spark plug replacement) then there could be a chance the recent repair is to blame…but you did not mention either of those items occurring.

Keep me posted will ya?


Austin Davis

About the Author:

Austin Davis, consumer car repair advocate. "Hi there! I love to help people solve their car repair problems and I hope my site was helpful to you today. Thank you for stopping by."