I'm surprised at the amount of information tossed out here that is incorrect. In the States, it's generally difficult to put a diesel nozzle in a gasoline fuel-filler. However, outside of the US, and including PR, it's definitely possible. Putting diesel in will also result in smoke and extremely poor engine performance. If the vehicle is turned off, there's a chance it won't start until all the diesel is removed from the fuel lines. But just for further clarification, the poor performance started all by itself, not after you put gas in at any time? Something with the story isn't adding up or something is being left out. But the key fact here is that you said you filled up at Puma. As I mentioned below and in the previous thread, Puma only has 3 different fuel options, not 4 (or more like at some pumps). It goes Diesel, Regular, then Super. There isn't a mid-grade option. If you put in the lowest octane number, the diesel handle was most likely grabbed. The number on the sticker wasn't the octane rating, but the cetane rating. And while I was in PR in November 2013, diesel at Puma was the cheapest fuel option.

Also, why add in $10 of gas after the fact if you're sure you didn't put in diesel?

Here's my post from the thread posted in the Alamo section:

I hate to say it...but you're responsible for the damages. Based on your statement, you filled the car with diesel. Did the vehicle start driving poorly shortly after a fill-up?

I was in Puerto Rico in November 2013. I do recall filling up at a few Puma gas stations. The Puma stations I visited had 3 different fuels to choose from. Diesel, Regular and Super. Diesel was about $0.15 cheaper than regular unleaded. It would also display the lowest number on the pump. Although, it would display a cetane rating, instead of octane.

Can you fit a diesel pump into a unleaded tank? Certainly! Sometimes it depends on the specific vehicle, as some have fail-safes, but it's actually quite easy to use the diesel pump inside a gasoline tank outside of the States.