I'm selling my car.. and over the past two weeks it has developed a problem. my car goes strong to 3,500-4k rpm but then has no power and won't rev any higher? but when not in gear reves fine to 6,5. any thoughts? has new TPS sensor, new water temp sensor, new head unit sensor. i'm thinking it might have something to do w/ air to fuel ratio? any ideas guys? i need to have her running mint by friday. thanx