House odor of doom - HELP!!!!!

[Steve S.]

Here’s the situation. House was vacant for 2 months without the air conditioner or heater from mid February through mid April. 

That was a mistake. Should have had the ac and heater running but didn’t expect it to be vacant that long. 

Started running ac a little each day in late April

New tenant moved in in June and there’s a horrible smell. 

They say it is noticeably worse when ac is running. 

Painted walls

Shampooed carpets

Deep cleaned tile grout. 

Ac guy says nothing obvious in the ac but wants to charge me $380 to clean the coils tomorrow. 

Carpet cleaners looked at pad and claim there’s not anything smelling in the carpet

Should I just give up and pull the carpet up?  

Last tenant had a dog. They claim they noticed no

Smell when they moved out. 

Help!!