Oor intermittened performance

[gabuchholz]

Sorry for the spelling , but I am on my iphOne. I have a 180sx stock, and it has a weird quirk. It runs like a dream almost every start, but with in 30mins of driving I do somthing to, it seems, stop the engine from getting boost. I have been able to sometimes fix it by turning of my car at a light for a minute, but that's only been tested a few times. I knowtisted today while going to work that my car while running like a 100hp car that around 2000rpm it revs very slowely till around 3000 when it revs fast but no performance... Any ideas? Thanks