Not another lifter tap and knocking thread :(


New Member
Oct 4, 2021
2002 GT, trying to diagnose a top-end tap, which most likely is a lifter issue. I was unplugging injectors one by one and when I unplug the #1 injector (front passenger), I get a rod knocking, unplugging the other injectors cause no dramatic effect, just the slight idle stumble one would expect. So what's going on here, do I need bearings? Do I need a Coyote crate engine?

Let me be clearer.

All 8 injectors plugged in, no knock.
Unplug any injector other than the front passenger, no knock, nothing really happens.
Unplug front passenger injector, knock, whether it's fuel or something else, idk.
Unplug COP and injector, no knock but rough idle (to be expected).
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