so this has done my head in...
over the last few weeks or so the car has developed a funky problem lol.
after an ECU reset its fine for a while then slowly gets worse.
at idle it runs rich and rough, at around 2000-2400rpm it leans out then above that it goes from lean to normal lean to normal in a wave kind of.

this only happens at part throttle and happens with the standard XH ecu, standard EL ECU and with a J3 with custom tune
full throttle is ok but not as powerful as it should be.

since owning the car ive changed fuel pump, TPS twice, map twice, plugs, leads, coil three times, coolant temp sensor, injectors, au fuel reg 3 times (standard and XR), fuel pump (walbro), dizzy (clean rotor and cap), checked cam timing, fuel filter, 02 sensor and fuel pressure reg.
it has 21"hg in vacuum.

so it kind of showed up after putting extractors and 2.5" cat on, so maybe suggests blocked cat, but it feels more spark or fuel related cause if i put my foot down it will accelerate.

anyone had a f**k cat that has acted this way?

tomorrow i'm going to put on another TPS just to be sure, ill put a gauge on fuel pressure and check back pressure in the exhaust.

if anyone has any suggestions please, go for it!
i'm out of ideas.
the only other thing i could think of is noise in the wiring, so may be worth changing the engine loom, but if i'm going to do that id rather do the AU swap at the same time (just waiting on info on the last 2 pins i cant figure out).

would a f**k radio suppressor near the coil cause issues like this?

sorry ive also checked the timing chain tension and its fine.
the only thing i have swapped is the AIT, but i didn't think it would have much impact on the way the car operates if it was f**k.
i have put a multimeter on most sensors and they were all outputting the right voltage, but obviously no way to be sure theyre not f**k without a scope.

i'm also yet to replace the knock sensor, would this be likely to mess s**t up if it decided to go spastic?
i'll also check the codes first thing in the morning.

if it started after fitting extractors and cat, it seems pretty obvious the cat could be blocked??

there is a slight chance the knock sensor could be randomly dumping timing, but I doubt it.. just unplug the knock sensor and see.....

otherwise I would suggest you may have a intake gasket leak

Disconect your o2 sensor and see what it does.
What extractors did you fit?

Have you checked the whole hose for the MAP sensor ???
Is the ISC valve clean ????....does it work properly ???

Check the vacume hose on the heater tap I had the same problem and mine was off.

there is no leak at all in the intake, even if there was it would not cause sporadic issues like this.
i did a code dump and it said the TPS is shorting to ground, so there may be an issue in the wiring loom.

i used that as an excuse to convert to AU ECU.
the cat isn't blocked, and again if it was it wouldn't be sporadic.
isc is fine as is the o2 sensor. nothing changes if i unplug the o2 sensor.
the o2 sensor is only a month old anyway.

i reckon it was just a coincidence that it started happening after i fitted the headers. they are pacemaker 4480s btw.

once i finish the AU conversion tomorrow i'll be chasing up the TPS issue by replacing the engine loom.

Does it sort of feel as if you're constantly driving into a 'wall of air'? Mine feels like this despite all the mods and it is because my cat is clogged with 16 years of burned oil and exhaust gases. Maybe invest in a new one or one pulled from another car.

EDIT: Just read that the cat probably isn't blocked. No idea, then. Hope you find an answer.