Gents,
What’s the condition of your crankcase breather hose(s)?
I have not seen ASR/limp since mid-Spring time but expect to at the first instance of cool weather.
For a long time I have been sold on the battery (6+ years old) as root cause because, if the problem is electrical, it is the only component that reacts to swings in temperature/high humidity so consistently, and whose gradual deterioration would coincide with the narrowing range of temperature/humidity in which the fault occurs.
Unfortunately, that decline seems to have leveled in the past year. This summer, despite the high humidity, and no battery maintenance, I have not (yet) had a single ASR/Limp event, which is odd. If the battery is failing, I would think it would be in its death throes by now but it is still going strong.
After my emissions test yesterday, HC numbers were higher than 2 years ago, and much higher than 4 years ago. The car passed with room to spare, but I remember when it was blowing zeros.
If HC is high then the engine is obviously running rich. The O2 sensor is new, MAF is fine, so somewhere else is an air/vacuum issue causing the computer to overcompensate with added fuel. Supporting this is the code 6 – faulty idle speed control -- the DM would return after going into limp mode, which I understand is airflow related. Finally, although my idle is very smooth, I sometimes feel random, minuscule bumps and rumbles as if the fuel/air mix is fluctuating in a small way, as if a leak somewhere is causing it to not be constant.
Is it possible the culprit could be my oil-leaking (and thus air-leaking) crankcase vent hose – the one that runs from the intake to the back of the water pump/tensioner assembly? Shown here:
http://www.peachparts.com/shopforum/showthread.php?t=296465
It is the only other visible component whose rate of deterioration would seem to coincide with the appearance, acceleration, and plateau of the ASR/Limp issue.
Is that hose designed to hold any measure of vacuum -- or, conversely, positive pressure? Could its leakiness create an implausible condition that throws the car into limp mode, particularly when the air is cold?