engine sometimes pings

[john1324]

I have a 2001 qx4 with a new re manufactured engine i use 91 0ctane fuel also fuel cleaner which helps my next plan is to change to ngk spark plugs and a new knock sensor I have no check engine light on what do you think? john

[atraudes]

Pinging can be caused by a number of things.

New spark plugs can help, though if they're not due to be changed I wouldn't bother. Try cleaning the mass airflow (MAF) sensor as well. It's also been recommended to give BG 44k a try:

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If you're not getting any power beyond 3000rpm, it may be a problem with the swirl valve:

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Have you had any other problems recently? How many miles have you put on the new engine?