1UZ + 440cc Injectors

[dansblackcat]

The tuner I used has done heaps of Wolf's and seems to know what he is doing.
Maybe the ECU is knackered.

What ECU's do the rest of you use?

[CrUZida]

Your ecu brand is fine. The wolf is more than capable of doing what you are asking of it.
440cc injectors on a stock 1UZ are fine (assuming the ecu is tuned for them).
I've done ~20,000km's with 440's and a Microtech. This includes mucho hwy km's, summer, winter, peak hour traffic, cold tassie, hot perth, aircon on, etc etc. All on the same set of plugs, have never removed them.

Its very strange that it seems to run fine for a couple of weeks, and then starts playing up. This could be the best place to start.
Have a look through the ECU, and see if any 'self learning' settings are enabled.
If they are, turn them off and get a retune. It could be that its getting bad information, and correcting in the wrong direction.

btw, don't try and diagnose fuel issues with sooted/fouled plugs, you'll end up chasing your tail.