We must be cousins. For the longest time, I wanted a 2003 Jetta TDI manual. But just before I left Toyota I procured a 2004 Corolla 5-speed. It was lower TCO, and especially for me since I got a huge discount on it as an employee. I had that car until the wife got T-Boned in it in 2019. And it still ran fine after the T-Boning. Yet the left side doors were no longer functioning. I drove it for a while all crunched up. Had to climb over from the passenger side. Not easy for a Shrek. But I got descent at it. Got lots of looks driving such a damaged car, but it drove really well. But I did eventually sell it for like $900. A heckuva car that was.
Look at it like this. You may buy a squirt more fuel for the Mirage, but that old Jetta will never come close to the TCO of the Mirage.
All vehicles start off (with a cold engine) in a richer fuel trim ... like a choke. So yes, they'll use more fuel until they warm up. Which makes me wonder. I wonder how much the mpg might increase by regular use of block heater? I think it was an option for this vehicle. I wonder if it might be an easy add. Time to do a search...
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View my fuel log 2020 Mirage ES 1.2 manual: 42.4 mpg (US) ... 18.0 km/L ... 5.5 L/100 km ... 50.9 mpg (Imp)