Lossing power

[lalinde89]

Hey guys! its happening something strage with my pathfinder, when im going up in a hill, and for example i need to pass from third to second gear the truck losses a lot of power. Yesterdar i had that situation so i need to put firts gear i the middle of the hill and everything normal ( a looooot of power, really a lot lol) but when i put the second gear the power went off, the revs go really down. Its the second time that happens and it is only when im in hills, if im in highways or normal streets everything its ok. anyone know whats going on??

[Slartibartfast]

Any codes/CEL? Otherwise I'd start by checking the MAF sensor and the vacuum lines.

[lalinde89]

Any codes/CEL? Otherwise I'd start by checking the MAF sensor and the vacuum lines.

Right now i dont have any codes, someone told that maybe could be the fuel pump cause it was going up hill when the problem appear.

 

btw the codes only can be obtain by a scanner?

[Slartibartfast]

Nope, the first-gen ECUs can be read by messing with a bit on the back and decoding the LED flashes. Here's the writeup: http://www.nissanpathfinders.net/forum/topic/21-ecu-self-diagnostics-for-87-95-pathfinder/

 

I'd be surprised if it was the fuel pump. Might try replacing the fuel filter, though, they're cheap and easy to get at, and a clogged one will give you all kinds of weirdness.

[lalinde89]

thx!im gonna do that!its strange cause the engine feel very strong always but in situations like that when i need to make gear down its worts because of the lack of power(only in really big hills)

[gv280z]

Manual transmission? It does great in first but shifting to second, when I'm guessing you've just about reached redline in first gear, right? So when you shift into 2nd gear the engine is bogging down, so it's not like the clutch is slipping and the revs are flying away, right? I think you might just want to go back to your basics: change your oil and filter, air cleaner, fuel filter, plugs, have your gear oil and diff oil checked, run a fuel system cleaner through there...is your truck carbureted? If so, your air fuel mixture may be off, your truck has enough power in first to climb the hill but not in second, going up in a higher elevation the air is thinner so you'd need to richen up the O2 in the carb.

 

If you've got an automatic and fuel injected, it may be the throttle position sensor is out of whack, you'll need to experiment with it to find the right setting. Loosen the screw SLIGHTLY and make tiny adjustments little by little and drive it everytime after each small adjustment until it seems like it's getting better. I'm really just grasping at straws here, I don't really know if that would help or not....If you can get any result at all, at least thats a start, a lead to build on. It could be a blocked exhaust that only shows you a problem under an extreme load on the engine, who knows.