Well, guess what...The hesitation problem is still here.
The car runs great on full throttle, it is faster than ever. Still, when driving in low rpms, you can feel it is not so responsive some times and you can't drive easily in steady revs.
To describe it a bit better, when you accelerate very smoothly (5% throttle) in 1st or 2nd gear when you go past the revs slowly you experience some cuts and drops in power and then it continues accelerating. It is not always a smooth drive. Also, you cannot hold the revs high at neutral. For example you want to keep 3000rpms in neutral and despite you keep the throttle stable, the revs go up and down. This doesn't happen when the engine is cold. Maybe due to more timing advance? I mean you can hold the revs up steadily using the throttle when the engine is cold. As soon it gets warm you just can't. The revs will fluctuate. You go to 2500revs and then they drop to 2200-2100 and then they go 2500 again slowly.
Finally the consumption can't drop below 8lt, even with economical driving.
I continue changing parts without result.
So far I have replaced
Dizzy,
Power cables
Water Hoses
TPS
RACV
Map
Fuel Pump
Checked for air leaks
replaced the intake manifold gasket
the o2 sensor is relatively new
The only thing i haven't checked is the Fuel pressure regulator..Could it be that?
Also, another thing I am not sure about has to do with the 4-1 header option and the dislocation of the o2 sensor far behind comparing to its original position. When you go for a 4-1 header the place for the o2 sensor is on the collector. The oem header has a 2 cable non-heated o2 sensor (one for signal and one for ground). The oem o2 sensor wasn't heated and thus it didn't work right when the gas temperature dropped, and this happened very often since it was dislocated. So, ever since (for the last 15 years or so) we placed a heated o2 sensor. The heated sensor is always connected to power. This is not 100% right but it has worked. Could it be that? I mean the sensors be ruined after some time due to the fact that the power resistance they bear is destroyed since it is powered constantly, even if not needed?
I am familiar however with the symptoms of a slow o2 sensor and i think this is not that.
Every help will be much appreciated..