2001 Pathy, multiple different codes, stalls when cold

[pathysteve]

Hey dudes, as the title says, i have an '01 pathfinder 3.5L 4x4 auto, engines stalls usually only once when its cold and you hit the gas for the first time. But mainly, every day a code comes up and i clear it with my scanner but a different one shows up the next day. Engine runs a little rough too. But there is good throttle response, however I've never driven a pathfinder before but it seems quite gutless on the highway. replaced an O2 sensor, that code kept coming back, so i changed it out. what would cause a different code everyday? not ALL the sensors can't be bad! its got 174,000kms on it. it gets about 12L/100kms. Thanks!

[atraudes]

Welcome to Nico!

What codes are you getting? There could be quite a few things going on, and the codes would be a great starting point. The loss of power you're feeling on the highway is likely due to whatever's going on, though "gutless" may just be relative. What type of wheels did you have before this Pathfinder?

[pathysteve]

just off the top of my head some of the codes are; P0300 random cylinder misfire, P0140 O2 sensor circuit no activity, and (not sure the #) crank position sensor problem. I had a dodge ram before this.

[atraudes]

I had a feeling a misfire would be amongst them. The spark plugs are supposed to be changed every 100k miles (160k km), so unless you know they are still in good shape, that's a good place to start. If you do replace them, be sure to only use NGK PLFR5A-11. People here have reported problems when using even slightly different plugs.

If that doesn't fix it or the plugs are still new, one of the coil packs is likely on its last legs. Unfortunately, P0300 is the generic misfire code and doesn't point to a specific coil pack. If you have a consistently rough idle, you can try to pinpoint the problem child by disconnecting the coil packs one by one while the engine is running and see which one doesn't cause the engine to stumble. If you end up buying a new coil pack, they can be had on Amazon for about $50 each new. Just be sure and buy Hitachi.

P0140 indicates a problem with one of the downstream O2 sensors, which makes it a low priority. They doesn't have a huge impact on engine performance and certainly aren't causing the problems you describe. It may even be kicked off as a result of the other problem(s) you've got going on. The crank position sensor was is probably actionable, though. The solution may or may not be to replace the sensor, depending on the code that's being thrown.

I would recommend driving for a few days and not clearing the codes. The specific cylinder misfire code should surface at some point after P0300 is thrown. That will also allow you to get the full list of codes.

If it still hasn't sprouted any chest hair once you have all of the codes squared away, I'd say replace your fuel filter if it's due. A clogged filter will choke the engine when you give it throttle.

The mileage you're getting is excellent, by the way! That was the EPA rated highway mileage when the car was made, so you're in good shape there.

[pathysteve]

the spark plugs are new. ill be changing the fuel filter (and transmission fluid/filter) this week see what difference that makes. To me, its acting like an o2 sensor, low kinda rough idle, and a lag/stall when its cold.

[atraudes]

It's possible. The reason I'm thinking it isn't the culprit is because I've read that quite a few members here either live with downstream failure or simply disable or bypass them. If you want to pursue it, there's some info on it in the EC section of the FSM, on page EC-279. It certainly couldn't hurt to get it taken care of; you'll want to eventually anyway

[Buzzman]

A flaky o2 sensor will not cause the stalling or drive-ability issues you are having.
From what I've read so far in your posts, I'm leaning towards a MAF sensor issue.
Try cleaning it and see what happens.
(Yes, to the fuel filter change as well. Never a bad thing to replace those).

[pathysteve]

ok, so i got the fuel filter changed, and the transmission fluid/filter change. At first it seemed to run a little smoother, and i was hopeful. I guess it does run a little smoother, but i was leaving work (engine cold) and it did it again, stalled as i hit the gas in reverse (no it doesn't only do it in reverse) to back out of my spot. I turn the key and it starts again fine, as usual. seems to run fine other than that. just a friggin pain in the a**. thoughts?

[atraudes]

I just had a thought: verify your fuel pressure and check for vacuum leaks. You should be able to borrow a fuel pressure tool from a parts store that hooks up to the fuel rail under the fuel damper. If it's not to spec (the FSM will tell you what the spec is), either your fuel pump is going bad or the fuel pressure regulator is stuck open. You can check the fuel pressure regulator by pulling the vacuum hose off while the engine is running and leave it off for a few minutes. If fuel leaks out of the vacuum port, the FPR is bad.

Checking for vacuum leaks is pretty easy. Run the engine and stick your head under the hood and listen for sucking or whistling sounds. You can use a can of brake cleaner (or MAF/throttle body cleaner) to spray bursts on the areas with hoses. If there's a leak, it'll get sucked in and cause the engine to stumble. If you don't find anything, rev the engine. Also check the intake ducting for cracks and tears. Just keep the brake cleaner bursts away from the hot exhaust.

[pathysteve]

ill try it, i have a fuel pressure gauge. but i have my doubts. do you really think this will cause and engine to stall only once, and only when its cold?

thanks

[barnaclebob]

When my MAF sensor was bad the car would almost stall when cold but as I pushed the gas pedal further it would then surge. Eventually on the highway it would kind of do the opposite, bog down, and loose all power. I was getting left and right bank too lean codes though.

[Buzzman]

MAF MAF MAF.
Make sure you get the Maxima MAF and not the Pathfinder MAF.
It will be considerably cheaper, and it's the same part.

[rgk]

If you're getting a crank sensor code, make sure your crank sensor A) has a proper (not loose) connection and B) has the correct resistance value (i.e. is working).

[pathysteve]

so, i haven't had the crank sensor code come on again (weird) but is still runs rough and stall when its cold. and now, the fuel mileage has gone to s***!! i was at 11L per 100kms... now its 16L per 100kms. WTF? I've had nothing but issues with this things. and it won't make up its mind as to which code it wants to throw.

[Buzzman]

You still haven't checked, cleaned or replaced your MAF yet, have you?

[pathysteve]

ok, so a few of the problems were solved with replacing the MAF, $165 canadian $$. it idles fine now which I'm very happy with. and i thank you all for that, although i don't like just swapping parts out, i would've liked to know how to properly check the MAF, but i threw a new one on anyway and luckily enough it worked! i just hope thats whats wrong with my fuel economy too. the only real problem i get now is random cyl misfire code, which I'm no too concerned about.

[pathysteve]

on another note, it shifts like a donkey kick even with the new fluid and filter.

[xracerx972]

1st to 2nd is a rough shift in almost all 97-03 pathfinders and qx4s..

When i got a p0300 on my 97 qx4, i properly set the ignition timing (distributor) using a timing light and i havent seen it since. Its worth the 5 minutes to verify your timing is proper. Mine also occasionally stalled in gear and had a random miss at times, almost like a fuel cut miss while cruising at about 50mph.. Since I set the timing and replaced the crusty old fuel filter, I havent had any issues.

[Buzzman]

i properly set the ignition timing (distributor) using a timing light and i havent seen it since. Its worth the 5 minutes to verify your timing is proper. Mine also occasionally stalled in gear and had a random miss at times, almost like a fuel cut miss while cruising at about 50mph.. Since I set the timing and replaced the crusty old fuel filter, I havent had any issues.

Unfortunately, the 2001 with the 3.5 engine doesn't have a distributor, and you can't set the timing. Kinda sucks, but that's the reality with electronic ignition.