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*sorry for the hijack*
I really hope that someone can help because I've been pulling my hair out on this. The CEL issue is really convoluted. I've been getting combinations of P1115, P1117 and P1119 (all O2 heater problems). The CEL literally turned on as the car was being driven onto the rollers for a smog check. Before that, I don't ever recall getting a CEL, even with headers, a EVO intake and GIAC chip in the last 5 years I've had the car. The only thing that had been changed was 1) installed a smaller, Braille battery several weeks prior and 2) pulled the EVO intake out and put it back in.
Since then, I've changed all the O2 sensors with generics (probably close to about time anyway--my car has 80k miles and is driven hard) and the MAF (again, probably about time anyway). The good news is that the car definitely performs better. The bad news is that the P1117 has been consistent and the P1115/P1119 is isolated to one O2 sensor. I checked the ECU to make sure there was voltage going to the O2 heaters on start up and also saw that the ECU was also signalling the O2 heaters after the car has warmed up to test for function. So the ECU seems to be fine.
The really weird part is that the pending codes clear themselves if I drive or even just rev the car above 3k RPM for a couple minutes. If I drive below 2.5k RPM (doesn't matter what speed), they come on and eventually light the CEL. I thought it may be related to the heat generated at higher RPM's, so I got some header wrap to keep the heat in the headers. That helped--the pending codes will clear at idle too and is less likely to come on at highway speeds, but will still come on at lower speed / lower RPM. So it seems to have something to do with heat or the higher temperatures help.
Now my current theory for the P1117 is that it is caused by a cat converter that is ready to fail. Watching the voltage on that sensor, it is fluctuates more than the post-cat sensor on the driver's side in those low RPM situations--cats work better when hot so that seems to make sense.
However, the P1115/P1119 is still a mystery. I swapped banks to see if it is wiring or the sensor and the code switches sides. So I bought a 5th sensor and wired that in. Same thing happens. Therefore, it seems to be the connector on that sensor and not the sensor itself, although cleaning it with electronics cleaner did not seem to help. In any case, higher revs / heat seems to help and the pending code is cleared at higher RPMs. In fact, it happens faster than with the P1117. Makes sense given it is closer to the engine, but doesn't explain why.
I don't care about the CELs as the car performs fine and passes the sniff test. It's basically a dedicated track car, but I do want to pass smog and finally get my tags. Hopefully someone has an idea.
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