weird knocking noise

[sydteg21]

ok, today i put on pfc which pretuned with similar set up i got , then drove home and sat in the car for a few mins when the car was on , then there was a werid knocking noise came up, it sounds like when you drop a thing on the floor or someone uses a hammer hit underneath the car , cos my feet could feel it every time it knocks , and it is random , came up once then 3 seconds later another one , then after thirty seonds three in a roll, any ideas what it could be , gonna put back on the stock ecu tomorrow, just wanna hear what you guys think BTW it never happend before until i put on the pfc, cos i definately would feel it if it happened before

[bigjo5]

did u change ur wheel or anything.. i had somethin similar like this few weeks ago and it was cause somebody tried to steal my wheel..so it was on 2 wheel nut at the front and made thsi knock noise and got louder as i got faster.

[sydteg21]

hey man, was idling

[fatboyz39]

sounds like a bearing. I would get it check out ASAP.

[sydteg21]

sounds like a bearing. I would get it check out ASAP.

hey man, u like to scare me or something , hehe, put back on the stock ecu, no knocking noise at all, can someone please explain that, don;t know nothing about the ecu

[90xsi]

could be running rich as, and misfiring so vibrating through the car