I have an 01 gt that when you get on it, around 3000 rpm it shutters a little bit. It's only done it a couple times now, but it has me wondering. It makes a shuttering, hesitant noise, then takes off again and I'm wondering if I could have a misfire?
Start with the easy stuff, Clean MAF, add some Seafoam, Fuel Filter, higher Octane of gas, change gas stations, air filter, Check PVC system, make sure there is not an abundance of blow-by going through the system. Pull the Cold air intake to see if the PVC is functioning. Blow-by fouls a lot of stuff. Pull the plugs.