Yea its the valve. First off, you are using the wrong fluid to clean it. Gasoline is not a good solvent for that application. Its like using gasoline to clean a carburator. The deposits are formed from the gas and as a result gas is a lousy cleaner. You need something much stronger. I use brake cleaner. I have found that all brands are not created equal. It will disolve carbon. And you really have to work at it.
There are several threads discussing this very topic. Several by me. I suggest you read them.
It is normal for the idle to increase when you remove the connector. Thats a good sign. But the valve is still dirty.
I got too many cars!! Insurance eats me alive. Dave
78 Corvette Stingray - 3k
82 242 Turbo Volvo - Manual - 270k
86 300e 5 speed manual - 210k
87 420sel - 240k
89 560sl - 78k
91 420sel - 205k
91 560sel - 85k
94 GMC Suburban - 90k
97 Harley Davidson Heritage Softail - 25k
00 GMC Silverado 1 ton 30k