When I use regular gas in my 91 Cherokee Laredo and step on it sometimes it just doesn't want to go. It'll hit about 3000 rpms and just tries and tries but can't throttle like it did. When I use better gas I can floor it and she has no problem. A bit of additional info is it was stolen and they took my lead fuel line that goes to the gas cap and put in a funnel so I'm sure lots of dirt got into the tank. I replaced my fuel filter hoping it'll help and it's still the same news. Bad fuel injectors? Clogged lines? Or what?