ECU issue. Need to reset after a day or so.

So here's the issue.

I got a new ecu and was using it for about 4 months with no problems. However now after a day or so the car will hesitate and sputter at any RPM higher than 5k. Boost or no boost. However the problem will immediately go away with a reset of the ecu. Like clockwork it will return after roughly 12-24 hours. Otherwise the car is totally driveable.

At first I had though that it was maybe the afm sending the wrong signal to ecu, but resetting the ecu only wouldn't solve the problem if that were the case.

I have only one cel and that is for a short in the o2 heater wiring. I have had that code problem for about 2 years (well before this problem began).

Before I start tearing in the car's electrical... anyone have ideas?

This is for a g-force ecu programmed with 550s and a t67. Car has supra impeller ct26 on st205 540cc with stock fuel pump.

I went through the daily ECU reset just recently. The ECU uses the O2 senser value it sees ritght now plus a 'stored' average which it remembers. That stored value gets reset when you reset the ECU. The engine runes better. But, the stored value gets trashed over time and the engine runs bad again until reset. I did not get any CEL codes at all. I put a new O2 senser in about a month ago and have not reset the ECU since.

Excellent info... since I didn't have the cash for a brand new 02 I simply unplugged it. All systems normal.