Cranks but no start!

[Supras7]

Hey guys hoping for some help. My 3.5 02 Pathfinder has been good to me since last year winter however this year I'm having a issue

Since the temperature dipped under -20 here in alberta I'm having a starting problem. It Cranks but won't start. Few tries while pumping the gas pedal it will fire up? I thought it might be a battery issue (but lights, radio, blower motor turn on fine) so I parked it with a battery trickle charger inside the garage overnight and it started up fine like normal the next day.

Drove to work parked it came back to start it 4hours later and same problem. Put a booster pack on it and did nothing. Pumped the gas pedal few times and started..

I've recently switched over to regular gas and maybe that's the problem? But I feel like it's more than that. I'm also getting poor gas mileage. About 320kms a tank. I had a faulty catalytic Code since I bought it but this is the first year I'm having a problem.

Should I seafoam or add some injector cleaner to the gas tank?

[Hawairish]

A lot of electrical components will work on a low battery, but it might not have enough CCA's to actually start the truck (or may not be charging properly). If you suspect a battery issue confirm that
1. The battery is, in fact, good. A quick check with a voltmeter should show something around 12.5V or better with truck off, closer to >14V with truck running (means alternator is functioning).
2. The battery connections are good; not corroded, not loose.

Are you using 5W motor oil?

Regular gas wouldn't be enough to prevent starting, but might affect mileage negatively. A faulty catalytic converter will surely affect mileage. What's the code?

Your local auto parts store can test the battery and retrieve the codes, if you don't have the means. But they'll probably hate you for making them work outside. If they want to test inside, though, be prepared to leave the battery with them so that it can thaw and/or be charged up. Best bet is to pull the battery and take it in with another vehicle, if you suspect battery issues.

[Supras7]

I suspect that it was the bad regular gas which caused the problem from a local grocery chain.

After using shell 91 it started fine..