Once in awhile I will get a knocking sound when I come to a complete stop, it sounds like engine knock but a little bit deeper. If I give it gas the knock will speed up. I have the Interceptor and I am not registering any engine knock when this happens. It will usually happen sometime within a few minutes of starting the car up and driving off after it is already warm. ex coming home from work for lunch breaks. Any ideas what it could be? should I worry if I am not registering any knock retard and the car runs fine?

 

i got that same prob

 

I have had the same problem. My guess is, here in md they're putting like 10% ethanol in our gas so that might be a reason. but i was also filling up with 93 at the local cheap gas station, i now only fill up with BP or shell. haven't heard it since.

 

I have heard that too... I acually run no less than 89 now and it seems to be gone or at least better. Gas quality sux and 87 is like not even 87 more like low 80's or who know what kind of $hit rating it has.

 

This comes up every few months on the forum. The usual explanation is the fuel pump pressure that makes the occasional little "knock, knock knock" sound within the first few minutes that the car's on or a few minutes after the car's off.

 

I know exactly what your talking about but I think he is getting at something else here. I hear the noise every once in a while also it almost sounds like a knocking valve or piston slap. Its def not "Knock" as in preignition.

I usually start my car and let it run for a minute or two before driving it, in the mean time ill go do something real quick like get the mail or a bottle of water and I hear it quite often when going to get back in my vehicle.

I have asked the dealer to look at it and they said nothing was wrong so I figured as long as I have it documented that I asked them to look at it thats all I can do.

ethanol is actually around 110-113 octane, still could be shitty gas though.