Clean the corrosion off the rotor. Usually I don't advocate fuel pressure tests because usually it provides no information. If the car starts, usually pressure is fine, if it doesn't pressure is not (other factors removed), but in this instance knowing if the system can hold the 2.8 bar is important and it should tell you if its fuel related or not.

Easy check would be engine temp sensor. Make sure its within spec. ~250ohms hot, 2000-3000 ohms cold depending on how cold it really is.

I have a AAA battery in my wagon...going on 5 years soon. Knock on wood!

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2016 Monsoon Gray Audi Allroad - 21k
2008 Black Mercedes E350 4Matic Sport - 131k
2014 Jeep Wranger Unlimited Sahara - 62k
2003 Gray Mercedes ML350 - 122k