Sluggish Driving

[adsdude]

I have an '02 WRX with 56,xxx miles on it. I got a check engine light about two weeks ago and took it to a dealership in Ocala. They charged me $95 to tell me that I had a misfire in the #1 cylinder and wanted to charge me $550 to change the spark plugs and clean the fuel injectors Well, I went ahead and changed the spark plugs myself and ran a bottle seafoam through the tank. I also changed the fuel filter, cleaned the MAF with MAF cleaner, and ran some seafoam through the vacuum lines. After all this, I haven't got a CEL for misfiring, but I did get a CEL for a small EVAP system leak, P0442. That CEL went away after a day or two though...
My question is this... before I got the first CEL (misfiring), the car seemed sluggish upon acceleration above 3000 rpm, almost like it wasn't getting enough fuel or air. The dealership said it was nothing, but I could feel a difference from when I first got it. The problem is still there, and it sounds like detonation when accelerating hard in 1st,2nd, and 3rd, so I am not driving around with any boost. I have no CEL right now. Could it be a vacuum leak? Bad fuel pump? Boost solenoid? I'm getting a Cobb AP soon (Monday). Is there a good shop I can take it to in Tampa or Ocala (besides a costly dealership)? Thanks in advance.

[adsdude]

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[EvoEatr]

A vacuum leak could explain your problem, however if you have a vacuum leak than you wouldnt be hitting target boost or holding boost, also chances are you would have a rough idle. To double check for a vacuum leak....with the car running take a can of 2+2 gum cutter and spray generously around the intake gaskets and all vacuum lines, if your idle changes you have found your issue. What mods are on the vehicle? as far as your EVAP leak, first check the lines you pulled off of the manifold to run seafoam through, than check the seal and tightness of your fuel cap....If you happened to accidentally leave the vacuum line off of the manifold for say the canister purge solenoid, that could def. explain both your P0442 and your "sluggish" feeling...

[adsdude]

The car is bone stock. I just bought it two months ago. I tried spraying starter fluid around the vacuum lines but maybe I didn't spray liberally enough. I'll try again, being more generous in spraying next time. As far as the EVAP leak, I just used the one vacuum hose that sits on the right of the BPV as the intake of the seafoam; it's attached. That CEL is still gone. Could the seafoam in my fuel tank have made a sensor collect wrong data or something?