bkool318

I am experiencing knocking noises after spirited driving or while driving locally. I hit the gas while in park and heard a small rattling noise as the car throttles back down. Also, when when coming to complete stop for light or stop sign, the car sometimes idles as if its going to turn off then revs back up to normal. When it makes the knocking noise, if I cut the car off and back on its gone. Infiniti states it may be left catalytic converter that needs replacing and indie shop states it may be lifter. Anyone know what it could be or had the same issue?

Link to knocking noise via YouTube-->

hurleyguys

your oil level good?

bkool318

yes, I'm about 900 miles in on a fresh oil change, I'm hoping an ECU reset and changing to ester oil will resolve, that's the only thing I've been seeing in forums

hurleyguys

the low idle might be a dirty throttle body. to me the knocking sounds like lifter noise. but there are def more knowledgeable people on here.

crookncastle

based on the video and your comment posted it sounds like top end noise. more than likely lifters are collapsed or weak. engine knock from the crank would get more frequent and louder as you accelerate the vehicle. if you have a stethoscope you can try to isolate which cylinder is making the noise. you can also use a stethoscope to listen at your catalyst to see if that is making noise. catalyst noise is usually a rattle and the noise you have is more of a loud tap in the video.