Rich running, high idle, and misfiring walk into a bar...
Good morning gents,
I have an ongoing issue with my 85 325e. For a while, it has been running rich. I has had an on-and-off misfire/stumbling issue. Lately, this got more interesting (and severe) and I would like your input. Here are the three symptoms:
1. Running rich. Sometimes more rich, sometimes less so.
2. Idles high. It varies between 1500 RPM and 2700 RPM when this issue is present. It never idles high when cold, but is now consistently idling high when hot. It is getting extra fuel and air somehow to cause this: enough to cause the high idle, and enough to give me unwanted power when going slowly: I can put it in 3rd at 20mph and accelerate to 25 and and beyond with my foot off the gas completely. It's weird to shift at 2500RPM and have your revs go up when you clutch out with your foot off of the gas.
3. Really bad misfire/stumbling issue happens when driving sometimes. The bad, not-all-my-power-strokes-are-happening-and-I-have-no-power kind that makes your car lurch back and forth. This usually goes on for a minute or two and then smooths out. Seems to be better at higher RPM if I can get there.
I thought of a vacuum leak, and replaced the hose to my ICV- didn't affect it. My intake boot is only a few months old. There could be another one somewhere. I did the test of taking the vacuum hose off of my FPR and waiting for an RPM rise. The rise did happen, albeit slowly and after a slight delay. The plugs and plug wires are recently new. The PO changed out an O2 sensor before I got the car (10k miles ago?). Could it have gone bad again due to an underlying issue and have this problem?
What should I look at next?