2000 pathfinder - p0133 and p0325

[cminor9]

Hey guys, my Pathfinder has been acting up again.

It had been running kind of rough, loping a bit at idle for the last two weeks. Also, it would occasionally die at idle (like at a light) sometimes if I don't get the RPMs up above 1000. It'll always restart with no problem. A few times it has hesitated a bit under load. I was driving on the highway and it didn't die, but it hesitated a few times and then the engine light turned on. It didn't quite feel or sound like a misfire (have had misfires in this car before due to a fuel pump), just a little bit of hesitation.

I found a small crack in the plastic intake tube right before the throttle body. I took the intake tube apart, cleaned it up, and put a small dab of blue RTV in the crack and reattached it. I thought that would fix the problem.

I just read the codes: P0325 and P0133. I know the knock sensor is a pretty common problem on these. The O2 sensor has showed up before as being slow.

Plugs, wires, fuel filter, air filter, distributor cap, fuel pump and screen were all replaced in late 2010.

I am kind of nervous about just replacing sensors, because they could just be reporting problems from other systems. If I have to, I had kind of been leaning toward trying the O2 sensor first, though, since it's easiest and cheapest to replace. Any other ideas before I just go throwing sensors at the problem?

[Towncivilian]

I'd replace the O2 sensor first - this NTK direct-fit sensor is $41.79 shipped from Amazon. Bosch is most likely the original supplier of the sensor, but the price is $70 vs $42. NTK is NGK, and from what I've read they make excellent products all around.

P0325 might be a side effect of P0133; the upstream O2 sensors have a say in the fuel/air ratio, and if one of the upstream sensors is faulty, poor fuel economy and performance (and thus possible knocking) can occur. Also make sure you always run 87 octane in your Pathfinder, nothing higher.

[cminor9]

Yeah, good suggestion on the NTK. I think I'll lean toward that. It seems much easier than messing with the knock sensor. I mean, I could pull all that off to get to the KS, but I sure don't want to lose a saturday like that.

[Towncivilian]

If you end up needing to replace the knock sensor, you relocate it somewhere more accessible (though this will diminish its accuracy at detecting knock) and just snip the current wiring and solder the new one in.

[cminor9]

well, I ordered a couple of those. Maybe I'll replace both front ones, and maybe I'll get better mileage. I have never replaced the sensors on it. I guess after 170k miles it's time, huh? For $40 bucks a pop, no big deal.

Hope you put a referral ID in that amazon link and get some money back on it.

I'll be sure to come back and tell whether it fixed the problem or not. Maybe someone else will be helped. This is one of the FEW sites that is actually helpful. Googling for automotive help is such a pain thanks to sites like fixya and justanswer.

If I have to do the knock sensor, I'll use it as an opportunity to replace the valve cover gaskets, all the hoses, and, and so on. The pathy has NO rust on the strut housings, and I'd love to be still driving the thing in five+ years. I've replaced the rack and pinion, and a lot of front end components. In for an ounce, in for a pound. And besides, having just bought a new car, this is all a LOT less than sales tax.

Thanks again for replying, towncivilian.

[Towncivilian]

You ordered a couple? The one I linked is for the upstream right O2 sensor only! You'll want this NTK sensor for the upstream left sensor. RockAuto has the lowest price for this sensor. Enter discount code 85597063729583 into the "How Did You Hear About Us?" box in the cart view for a 5% discount.

You're welcome, and good luck!

[cminor9]

You know, it didn't even occur to me that they would be different on each side. That's the craziest thing I've ever heard. Ok, well, maybe not the craziest but still.

I'll do some checking before I ordered. I looked at the FSM and it didn't seem to indicate the left front bank was any different from the right front bank.

[Towncivilian]

The wiring harness plug is different between the two.

[cminor9]

well, I got the new 02 sensor in last night and cleared the MIL and the codes.

I pulled up to a stop sign today and the engine died while waiting. It restarted immediately, and ran ok afterwards, but there is still some kind of a problem going on here.

If I keep my foot on the gas at a stop light (and a foot on the brake obviously) to keep the RPM at or above 800 it never dies. If I leave my foot off the gas, the idle will sometimes gradually drop low (right above 500) and it'll sputter and die. I don't seem to have the problem with the engine is cold, only when it's hot.

The computer hasn't thrown a code yet, but I did just erase the codes and I suspect it'll come back on as I keep driving it. Any suggestions?

[Towncivilian]

Check for air intake leaks and ensure that the air filter is sealing well. Try cleaning the throttle body & idle air control valve as well. Use a can of throttle body cleaner for both.