Weird CEL thing..
I have an OBD 1 reader for my 94 merc, but lost the paperwork for it. I'm still looking and will try to download the book from the web.
In the meantime, I have a CEL that only comes on at NIGHT. In the daytime, I can run with the lights on/off, the heater on, then AC, 75mph for hours, doesn't matter, the CEl stays off.
But, on the way home from work about 2 am, after about 15 mins of running down the highway, the CEL comes on and stays on until I turn the car off and restart, then about 15 minutes later, it's back. Next day, in the daylight, no CEL all day. When the light comes on, there is no noticable affect on my performance, car still runs great.
So, I'm thinking some sensor in the emissions system is struggling with the cooler, damp air at night. Opinions anyone?
My job, basically is to think up Goofy Sh*t.