I have an 86 740 Turbo. First, within the past few weeks I have noticed that the battery charge guage on the instrument panel is in the red but the car starts ok, Wondering if the battery is dying or if it's the alternator? Second, back in July I took it on the HWY for a weekend, a few hours drive in each direction, it has had a rough idle ever since and just dosen't sound the same, and at about the same time I noticed that exhaust is coming through the vents, especially noticable when stoped/idling. Any suggestions?

 

1. Check the output of the Alt. with a digital Volt meter.

2. Check for an Exhaust leak. Also when was the last tune up and throttle cleaning?