I’d love to know which cars you drive with 5-6 l/100km

Could be an inquiry, could be a statement of disbelief. Up to interpretation.

I’d love to know which cars you drive with 5-6 l/100km lol

The “lol” at the end makes it read like your accusing the other commenter of lying and that you think this is an impossible to reach fuel consumption.

Additionally, many people don’t like huge pickup trucks and worshippers thereof. You might have slipped into that category in their understanding.