Nasty Spark Plugs/Idle on 1990 325i

[mattbaz]

I have a 90' 325i with at least 500k on the clock (it's on its third speedometer, and I figured a working one was the least of its problems). I recently took it from Arizona to Kentucky and back. When I got to Kentucky, the idle would stay very low until it would warm up (sometimes stalling), at which point it would run perfectly. The same thing happened to me 3 years ago and I fixed it by replacing vacuum hoses and installing a new ICV. I didn't have a chance to do anything while in Kentucky.

On the way home, I got stuck in a bad storm in New Mexico, and the car ended up running solid (except gas stops) for over 30 hours because of bad conditions and booked hotels. It made it back to Arizona, but the idle problem was worse and the engine sounded very rough (understandably).

I changed the oil and cleaned the ICV. It still idles low but doesn't stall. It sounds very rough and smoked a lot at first after I reinstalled the ICV. I couldn't find a vacuum leak, and the oil cap is slightly cracked. I checked the plugs and they were disgusting; completely covered with a thick, dark, gray stuff that's halfway in consistency between gas and oil. It didn't look like any oil-fouling I've seen before, and it was on every plug. The air filter is also filthy.

I have maintained the car myself for years and have never missed any scheduled maintenance (though I might do things early because of my broken odometer). I'm going to replace the plugs, oil cap, and air filter, adjust the valves, put in new vacuum hoses and replace the fuel filter no matter what, but I want to know if those things could account for the idle and plugs. Is it possible that I need to replace valve stem seals or piston rings? Put in yet another new ICV? Anything else I might be overlooking? I don't think I have any major maintenance coming up.

I know it's old and probably a miracle it's running anyway, but I'm pretty attached to the car. I really enjoy the DIYs on the site and figured one of you might be able to give me some good suggestions. Thanks in advance for the help.

Matt

[mattbaz]

Also, if it helps, the compression is relatively good and more or less uniform for all cylinders.

[Jeron]

I'd figure out what is in the oil first.

Are u sure it isn't coolant?

You could send it to Blackstone Labs and have the oil tested.