madporsche

Once I give a full throttle from 2nd gear, I get a hesitation in acceleration between 5,000-6,000rpm. Actually, the RPM shortly goes down in the range @ WOT. If I gently control the gas pedal though, the symptom doesn't bother me. Besides the range I mentioned, my 07 GT3 runs great without any power loss or hesitation.

Is it caused by bad MAF? Any ideas?

BBMGT3

Misfire. Ignition coil / camshaft actuator / plugs / fuel pump. Had the same thing, similar rev range, same car. In my case it was the fuel pump one time, then the fuel relay, then the ignition coil. Was irritating as hell to fix it because it was an intermittent problem but eventually was sorted. You're probably losing 20hp or something too. Hard to feel but comparing track data before and after I would reach about 5kph higher top speed at the end of the straight on the track.

stujelly

If it was a 3.8 gt3 or rs I would say cam actuator. Is the valve train making any more noise than usual?

madporsche

No more noise than usual
Can GT3's racing gear ratio cause the issue?

BBMGT3

no

Carrera GT

Don't keep asking the engine to suffer through this problem it could turn ugly in a big bang.

These points of failure make sense, but mid-range torque can be all kinds of gremlins or evil hobgoblins -- if the engine had an over-rev, it can be in the valve train or the big end and getting worse. If it's electronic, it can be as simple as a mouse chewing into a wire and causing voltage faults. If it's in the engine system loops, it would throw emissions codes and you'd get an OBD2 CEL.

Since the engine is losing rpm (that's a worry) then regaining and building power, I'm guessing it's a known problem with the engine at this age and mileage, maintenance history, fuel and driving habits. It's time for a diagnostic trip to the dealer -- they'll probably pick up the fault without guesswork since it's repeatable and has a dramatic symptom.

BBMGT3

Absolutely. A durametric check will reveal everything, including overrevs. When they did my check, they were pretty exhaustive; they swapped coils, plugs, did leakdown tests, checked each fuel injector, and so on.

TTurbine

Check Flywheel ,

Had a similar problem but with misifire and the car would run like it's on 4 cyl , They dealer and a reputable swiss tuner thought that it was a Cam related problem , Durametric throwed out a camshaft related fault , turned out to be a flywheel bolt