Seafoam is NOT a good cleaner. It just isn't.
Did you know that the company that sells the stuff is named "Seafoam SALES Company" ??
Sales is about all they are really good for.
There are better stabilizers and much better cleaners available........at about half the price.
Give it double shot of Berrymans B12 Chemtool or Gumout.
AND......if you are testing with no air filter in place, that alone might be causing the problems you are having.