My 89 xt6 with a 2.7L was jus put back together with new hlas, new oil pump, new injectors, new fuel filter and a couple more stuff. It has a loud tapping noise that will come and go. For example, I can start in first gear no tapping, get up to 3-4k rpm and it starts tapping, I'll shift into 2nd gear and it will stop and maybe come back maybe not. It will also do it at idle when I first start it up. Anyone have any suggestions?

describe the tapping and details more for us to diagnose something like this over inter webs.

1. why was all this work done?

2. Did it tap before?

3. Sound is what - High pitched, low, rhythmic, comes and goes for how long?  Does it sound like typical older Subaru HLA tick or something else?

4. is it emanating from right or left side of engine or center or front or under the car?

5. what do you mean by “new” oil pump?  They’re not available new, so it’s either a different used one, or you went through some effort to find and use a new one which suggests issues being chased you didn’t mention. Did you install a new shaft seal and Mickey Mouse gasket with the pump?

Likely possibilities:

1. The bell housing cover plate under the vehicle is loose and moving or vibrating

2. TOD - HLA tapping. 

3. Exhaust rattle or leak - they can sound mechanical and rhythmic due to loading being as such  

 

Sounds like lifters... Sometimes it takes hundreds of miles to go away. Try starting your car during the warm part of the day does it help?