Looking for opinions while troubleshooting an issue with my pathfinder.
The car has been running fine. There is a check engine light on for bank 2 CAT which has been on for about a month.
The other day I filled the tank with regular 87 octane fuel which I sometimes do.
Shortly after leaving the fueling station, while climbing a steep hill the engine started cutting out losing power.
The engine never shut off and I was able to make the top of the hill. I turned around headed back home under reduced power.
The car starts and idles fine. It loses power under acceleration.
My first instinct was bad fuel. I checked with the station and the manager said he had no other complaints.
I disconnected the fuel line from the rail and filled up a clear glass with the fuel and let it set. No separation.
I plumbed a pressure gauge between the fuel line and the rail and I get a steady 50 lbs. pressure at idle.
When I power brake the car in drive the pressure drops off to 40 lbs at about 3k rpm.
I added a bottle of octane booster to the tank and took it for a ride. It runs a little better but still lacks power.
Still not throwing any codes other than the cat.
Thinking it might be a fuel pump, fuel filter or cam sensor issue?
I have a scan tool with a live data feature. Anything I should be looking for?
Any ideas? Thanks in advance.

anything like this? loss of power could be plugged cat....exhaust...since we have two of them, it could be one side...etc.

This is Frontier 4 banger in the video, but it seems close enough in relation.

Eric O is great and shows a lot of his ideas.testing methods and information that might help.

https://www.youtube.com/watch?v=UlkO235 ... oRepairLLC

Thank you for your response.
Eric O is the man.
You could be onto something.

I replaced the right front CAT in the spring. I'm getting a code for the left front CAT and I was going to replace it soon.
My scan tool tells me that both cats are running at the same temp. I'll check with a thermometer.
Then I think I'll disconnect the CAT from the exhaust manifold and see if the symptoms clear up.

Thanks again. I'll post back to let you know.

I actually saw something on another Nissan that caused loss of power under acceleration.

The rear brake light bulb caused it.

The filament/bulb was broken(inside), and it caused an occasional short and the ECU thought the PNP switch triggered. Caused the vehicle to go into a temporary limp mode.

It was seen only when driving, with a scan tool connected.

How about that.

It's not the PNP, it's that the TCM's on all CVT Nissans look at the brake lamps and positively refuse to accelerate if they think the brakes are applied. The Versa bubble cars, which are infamous for crappy taillamps, actually throw a code over it if the reverse and brake circuits get crossed by moisture, P0705. We sell a lot of those taillights, but customers often don't want to believe their boggy performance is being caused by a busted one.

My Mistake!!

This fella found it in a Nissan Frontier, but it's my mistake.

Not the PNP, it's the stop lamp switch. Claims no codes, etc. Broken tail lamp.


https://www.youtube.com/watch?v=OQrqkMC ... veInaction

TooMuchControl wrote: ↑

Fri Feb 23, 2024 4:36 pm

My Mistake!!

This fella found it in a Nissan Frontier, but it's my mistake.

Not the PNP, it's the stop lamp switch. Claims no codes, etc. Broken tail lamp.

Some (but not all) of the conventional tranny TCM's do the same thing. That guy's Frontier is evidently one of them.