Rod knock

[kx250]

Hi all, I have an 04 Explorer with the 4.6. On start up I have a slight rattle that sounds like a rod knock for about 2 seconds then it's gone. If you tap the gas petal you can here it again. It goes away around 2000 rpm. How do you tell if it's the timing chain or the torque converter. Thanks

 

[Diff Whack Daddy]

I am not sure of the set up on the 4.6L, but on the 4.0's a similar sound is there on start up and in my case it's usually a dry lifter. The Ex sits for weeks at a time, allowing the hydraulic lifters to drain and the clank like crazy until they get oil again.

When we replaced Painter Ken's 4.0, the motor we used sat for a year without running. On start up it sounded like it was going to blow up with all the knocking. But after about 5 minutes or so she was quiet and running smooth.