Hey all,
I've been having this issue for over 2 years now and am hoping someone might have an idea on what it might be caused by. I've searched around the forum a bit but haven't really found an answer. Generally, this will pop up every once in a while, and then somehow, goes away for a bit. What happens is the car all of the sudden loses power, often on uphills at speeds over 30mph or so. At that point, I can't get it to go over 25mphs or less without pushing the RPMs way up.
Latest issue:
I drove about 180miles on last friday on highways without issue, drove around during the wkend and it was fine. Then on the drive home, heading up a long hill, had total loss of power. I tried to push it to see if the engine could push through it, pushed the rpms up to 4000, from normal 2500-2800 while driving on highway. Stopped at the top of the hill to check under the hood and saw what I think was the exhaust manifold (lower driver's side of engine) glowing red. Engine temp gauge barely moved, if at all. Decided to delay the trip home, headed back down the hill and took to a mechanic in the closest town. He reset the codes, and then driving 20-30 miles, could not replicate the issue and I decided to just drive it home and hope for the best. On the drive home, again had the loss of power which lasted for maybe 20-30 miles, where going up hills, it was sluggish and I could barely maintain 20-25mph, then on the downhills/straightaways, I could get back up to 45-50mph. After that, it seemed ok, but I didn't really push it. Now it seems fine driving around town, but no highway driving.
Repair history:
I first took it in to get it fixed to an AAMCO thinking it was a transmission issue, and they said it needed some kind of new transmission computer that would be $3k. Took it to a smaller shop for 2nd opinion and they said it wasn't transmission, if it was intermittent. They thought it was the chain drive wearing down, causing the engine to shut down or not run properly. So I had them replace that for 1800$ and it drove fine for a few weeks, then the issue popped back up. I took it back in and they looked it over for a couple of days. Finally decided it was due to Nissan's apparent sensitivity to oil pressure? Said the oil was overfilled. So they changed the oil, gave it back and it ran fine for a few months. Then the issue popped up again, so i got another oil change and it was again fine for a while.
Some other info
SES code p0420 has been going for a while but I assumed it was a sensor issue and didn't fix. Now I'm assuming that this is related to the problem
It has a slow oil leak, but I usually top off and don't think that's an issue
'03 Pathfinder - loss of power/sluggish acceleration
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atraudes
- Posts: 1106
- Joined: Thu Jan 10, 2013 7:46 pm
- Car: 2001.5 Infiniti QX4 4WD
- Location: Sammamish, WA
Re: '03 Pathfinder - loss of power/sluggish acceleration
Those are some bizarre symptoms 
Right off the bat, though, I'd say to focus on that P0420 code. It never makes sense to run down one problem while the car's trying to tell you something, and I could see them being related.
I have a couple clarifying questions.
- When you say you have to push it uphill and you were bumping the RPMs to 4k, was the engine revving fine and you had a feeling like you were towing an anchor, or was it that the engine bogged down like the oil had turned to thick molasses and you were having to give it more throttle to maintain RPMs? It sounds like the latter, but I wanted to make sure.
- When you saw the driver's side exhaust glowing red, was the passenger's side glowing too?
- What sort of mileage are you getting?
- Any smoke after starting it?
In regards to the code, it's an indication that the passenger side catalytic converter is operating below threshold. Very, very occasionally just replacing the downstream passenger side sensor will remedy it, and some people have had luck with a sensor spacer, and others have had luck just filling up with premium instead of regular. I had 0420 and 0430 (driver and passenger cats) when I bought mine and ended up replacing both catalytic converters and both downstream sensors, which I think is the most common remedy.
My loose theory is that the passenger's side cat is plugged up and increased loads (like going uphill) exacerbate or amplify this problem. The engine not being able to kick the exhaust out properly would definitely explain an engine going maple syrup on you. I'm thinking it's like breathing through a straw: not a problem while watching TV or walking around, but it causes huge problems when you go for a jog.
It's not a cheap repair, so you'll probably want to search for P0420 on the forum so you can see what other people here have found and done. The part's a bit spendy ($3/400) and probably not something you can do yourself. I'm very inclined with a wrench, and am still glad that I let someone else do it. The bolts are inconveniently placed to say the least.
However, if replacing the cat(s) ends up fixing it, you likely have other problems which you should look into. Cats don't just go bad. On a well maintained engine, they should easily last as long as the vehicle. They generally fail because the engine is running rich, due to poor combustion (poor quality gasoline, too low of a grade) or things like leaky or stuck injectors, bad fuel pressure regulator, bad air/fuel/exhaust sensors, etc. You can burn that bridge when you get there, though.
Right off the bat, though, I'd say to focus on that P0420 code. It never makes sense to run down one problem while the car's trying to tell you something, and I could see them being related.I have a couple clarifying questions.
- When you say you have to push it uphill and you were bumping the RPMs to 4k, was the engine revving fine and you had a feeling like you were towing an anchor, or was it that the engine bogged down like the oil had turned to thick molasses and you were having to give it more throttle to maintain RPMs? It sounds like the latter, but I wanted to make sure.
- When you saw the driver's side exhaust glowing red, was the passenger's side glowing too?
- What sort of mileage are you getting?
- Any smoke after starting it?
In regards to the code, it's an indication that the passenger side catalytic converter is operating below threshold. Very, very occasionally just replacing the downstream passenger side sensor will remedy it, and some people have had luck with a sensor spacer, and others have had luck just filling up with premium instead of regular. I had 0420 and 0430 (driver and passenger cats) when I bought mine and ended up replacing both catalytic converters and both downstream sensors, which I think is the most common remedy.
My loose theory is that the passenger's side cat is plugged up and increased loads (like going uphill) exacerbate or amplify this problem. The engine not being able to kick the exhaust out properly would definitely explain an engine going maple syrup on you. I'm thinking it's like breathing through a straw: not a problem while watching TV or walking around, but it causes huge problems when you go for a jog.
It's not a cheap repair, so you'll probably want to search for P0420 on the forum so you can see what other people here have found and done. The part's a bit spendy ($3/400) and probably not something you can do yourself. I'm very inclined with a wrench, and am still glad that I let someone else do it. The bolts are inconveniently placed to say the least.
However, if replacing the cat(s) ends up fixing it, you likely have other problems which you should look into. Cats don't just go bad. On a well maintained engine, they should easily last as long as the vehicle. They generally fail because the engine is running rich, due to poor combustion (poor quality gasoline, too low of a grade) or things like leaky or stuck injectors, bad fuel pressure regulator, bad air/fuel/exhaust sensors, etc. You can burn that bridge when you get there, though.
Re: '03 Pathfinder - loss of power/sluggish acceleration
atraudes, thanks a lot. Very detailed reply, I feel like I have a much better idea of what might be going on. This is great.
Yes, bizarre symptoms, frustrating situation to say the least. This car towed a uhaul trailer from Boston to Oregon without issue 3 years ago but since, it has been fickle for sure.
To answer the questions:
- The latter, it seemed like engine was bogged down and I had to push harder/rev higher to maintain any kind of momentum/speed. More throttle to maintain speed but the RPMs revved way higher than normal.
- Driver side exhaust glowing red but of course I did not check the passenger side
- I think I'm typically getting 16-18mpg. I don't check it religiously but usually check when I fill up, especially since the gas gauge doesn't work so I have to always track the mileage.
- Typically no smoke but there was smoke when I had the issue driving a week ago. I know there's a slow oil leak, one local place said it wasn't worth fixing because it was such a hard to get at spot, and just to keep an eye and top off. So, possibly a symptom of my non-knowledge, I just assumed the engine was hot and the smoke was leaked oil burning off.
When you say "the part is a bit spendy", you are talking about the one cat right? 3/400$ for the part to replace the passenger-side cat, am I reading that right? Just trying to get an idea of what different options may cost. As you suggested, I'd probably have someone do it unless it was a real straightforward part swap. Any suggestions on the type of shop to take it to? As I said in my original post, I've had all sorts of answers from a few different shops and don't have a place in town I use all the time/really trust. Exhaust-specialist type place?
Thanks again, really appreciate the thoughts and ideas.
Yes, bizarre symptoms, frustrating situation to say the least. This car towed a uhaul trailer from Boston to Oregon without issue 3 years ago but since, it has been fickle for sure.
To answer the questions:
- The latter, it seemed like engine was bogged down and I had to push harder/rev higher to maintain any kind of momentum/speed. More throttle to maintain speed but the RPMs revved way higher than normal.
- Driver side exhaust glowing red but of course I did not check the passenger side
- I think I'm typically getting 16-18mpg. I don't check it religiously but usually check when I fill up, especially since the gas gauge doesn't work so I have to always track the mileage.
- Typically no smoke but there was smoke when I had the issue driving a week ago. I know there's a slow oil leak, one local place said it wasn't worth fixing because it was such a hard to get at spot, and just to keep an eye and top off. So, possibly a symptom of my non-knowledge, I just assumed the engine was hot and the smoke was leaked oil burning off.
When you say "the part is a bit spendy", you are talking about the one cat right? 3/400$ for the part to replace the passenger-side cat, am I reading that right? Just trying to get an idea of what different options may cost. As you suggested, I'd probably have someone do it unless it was a real straightforward part swap. Any suggestions on the type of shop to take it to? As I said in my original post, I've had all sorts of answers from a few different shops and don't have a place in town I use all the time/really trust. Exhaust-specialist type place?
Thanks again, really appreciate the thoughts and ideas.
-
atraudes
- Posts: 1106
- Joined: Thu Jan 10, 2013 7:46 pm
- Car: 2001.5 Infiniti QX4 4WD
- Location: Sammamish, WA
Re: '03 Pathfinder - loss of power/sluggish acceleration
Looks like I'm not remembering the price of the cats right. I thought I remembered spending $300 each, but I see them on Amazon for $230 each. I got the Walker 16343 and 16344, which is a decent brand. Flowmaster, Magnaflow and some others make high performance versions as well.
I would definitely not try to do it yourself; it's anything but straightforward. Half of the bolts are pressed up against the firewall and are barely even visible. I had a local gas station shop do the work, so I imagine any repair or exhaust shop would be able to do it.
Are you really only getting the one code? It's a little odd the other side isn't below threshold as well, especially considering how long the code has been there. Though I could see a leaky injector just killing one side of the exhaust... I don't know how recently you pulled the codes, but local parts stores will do it for free; it may be worthwhile to see if anything's changed.
You get some decent mileage! I track my mileage using an app and get 14.5 on average, though I have a heavy foot
If your mechanic said it's not worth fixing the oil leak, I'm betting it's the rear main seal, which is around the crankshaft. You have to pull the engine or transmission to get to it.
I have my fingers crossed!
I would definitely not try to do it yourself; it's anything but straightforward. Half of the bolts are pressed up against the firewall and are barely even visible. I had a local gas station shop do the work, so I imagine any repair or exhaust shop would be able to do it.
Are you really only getting the one code? It's a little odd the other side isn't below threshold as well, especially considering how long the code has been there. Though I could see a leaky injector just killing one side of the exhaust... I don't know how recently you pulled the codes, but local parts stores will do it for free; it may be worthwhile to see if anything's changed.
You get some decent mileage! I track my mileage using an app and get 14.5 on average, though I have a heavy foot
If your mechanic said it's not worth fixing the oil leak, I'm betting it's the rear main seal, which is around the crankshaft. You have to pull the engine or transmission to get to it.
I have my fingers crossed!