I have a 2006 Scion xA 1.5 liter. It has 110,000 miles on it. It has good acceleration. The exhaust is completely new from the exhaust manifold all the way back. The timing chain, from all gears, is new. The oil pump and everything under it (all sensors - cam sensor, crank sensor, etc.) is new. The only thing I have not changed is the knock sensor. It runs beautifully, but when stopped at a red light it makes a knocking sound that stops if I put it in park. From the AMF toward the intake it is clean and the screen attached to the intake is new. If I hold the huge hose from the AMF toward the intake the noise stops. I wrapped a bungy cord around that big hose to the left of the body and the noise lessened. Has anyone else had this problem and do they have any suggestions to resolve it? Thanks.
The knocking does it happen once or is it non stop? If you give it gas does it stop? If you put it in neutral, park or reverse does it go away or lessen? Can you pin point the location or have a good general idea where it's coming from. If you accelerate heavily does it happen or between shifts. Lastly does outside or running temp effect it.
It happens only in drive. If I put it in park or neutral it stops. It stops if I step on the gas. It is not affected by the temp, either outside or running. It never happens when moving or between shifts.
I would check your motor mounts. Sometimes it can be very easy to over look and miss a broken/ cracked mount so really inspect them.
A video or sound clip would be helpful if possible
Check for loose flex plate bolts.
I checked the motor mounts. I replaced them 1 1/2 - 2 years ago. They were all good. I started thinking about why it lessens when t tie the bunny cord tight and realized it must be pulling something together. I went to check everything inside the cord and found a tiny crack in the intake manifold. I have ordered a new one and a new knock sensor. I will post if changing those things fixes the problem.