Di yata sa unit... more likely sa fuel station mismo.

Take this as an example... maraming horror stories from certain areas regarding Toyota fuel pump failures... but I personally know four or five D4D owners at or around 100,000 kilometers with no problems.

I've never had problems with test units... ever... but I filled up once at a provincial station that I'd never used before and got one test unit into limp mode, from water contamination.

It's all about your local stations. Nakakainis lang, nobody is enforcing fuel quality standards here. Heck, even the gasoline in some brand-name stations is suspect!