Just joined vwwatercooled. I've had my Transporter for over 20 years and clocked over 500K on the odometer. It's been a work, family and gig bus over the years, and is now showing real signs of wear and tear. I've done a lot of the easy maintenance jobs myself and regular servicing. Recently I had 3 breakdowns, 2 due to cooling system plastic junction parts failing and one computer malfunction. I'm slowly rebuilding the cooling system with new hoses, tanks etc.

However, since the electrical breakdown it's been running rough. I've replaced the distributor and leads, also new fuel pump, cleaned the throttle body, new fan belt, checked the timing and it's running better - but the idle speed fluctuates and acceleration is sometimes hesitant. I'm wondering if someone has had similar problems and found the root cause to save me from further trial and error! I'd welcome some good mechanical advice to get this mystery solved!