Not sure if you expect us to feel bad for you or something. It's given 18 years of great service and things wear and break just like any car. Don't buy a used car if you can't afford to fix it, or don't have the mechanical aptitude to work on it yourself. Just buy a warrantied camry and trade it in every couple years. These cars to me are way nicer and cooler than a honda or toyota, so I'd rather use my own time to fix it.

My advice to you is replace the alternator or regulator and sell it. If I lived closer I'd give you $400 for it and drive it for another 150K miles.

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Only diesels in this driveway.
2005 E320 CDI 243k Black/Black
2008 Chevy 3500HD Duramax 340k
2004 Chevy 2500HD Duramax 220k