Engine light strange circumstances
Speaking of weird engine light (MIL) coming on circumstances, mine 1st came on a few weeks ago.
I bought an ELM-327 usb ODBII interface with software for my laptop off ebay to diagnose the fault code. Hooked it up to the car, read the fault code which claimed the cat wasn't running efficiently. ok, all seemed logical so far.
Filled up with a different brand of petrol, used the laptop to clear the fault code, fine. Checked lambda sensors were operating normally, fine. All seemed well, until;
A couple of weeks later, driving on the exact same stretch of road, same thing, light came on, fault code returned. Repeated above procedure to clear fault code.
Happened twice more since, when travelling at about 60mph under different weather conditions, wet or dry, but (not on any other motorway or road, and I drive all across the UK) ONLY on that EXACT same stretch of road!
Now I'm thinking this road has very high embankments at the sides so perhaps there's some kind of weird air turbulence, wind tunnel effect or vacuum thing going on that is depriving my air intake or blowing into the exhaust, making the car run artificially rich on that stretch of road ?
I don't think it could be a hard fault with the cat or the fault light would come straight back on when the sensors warmed up enough to go closed loop every time the car warmed up, and it doesn't.
I'm puzzled about this one.