front left fender wall. It has three plugs and a vacuum line going into it is all black. These are pretty hardy so i would be surprised if it is this but new they are pricey i would look for a used one for around 100 bucks. Have you had the coil checked out yet.
2005 320 CDI
2006.5 VW Jetta TDI
1991 560SEL (179000 Sold)
1972 280SEL 4.5 ('The Lead Sled' 320000 miles when sold.)
1972 220D (225000 when sold)