Pathfinder loss of power at take-off and on passing on highway

[capelahave]

2001 Pathfinder- My pathfinder has no power. At passing speeds 50 - 60 mph when trying to pass the engine revs but the truck does not go any faster,.I have changed O2 sensors and checked Catalytic convertors no help. It is like the engine is plugged. My mechanic has run out of ideas. Has anyone else had this problem?? I had a Po140 code but that is gone now that the O2 sensor is changed.

Please help!

[Buzzman]

Just so I understand: The engine revs up, but it doesn't move any faster?Are you sure it's not a transmission problem?The only other thing that I've run across that might be worth checking is a collapsed (internal wall) exhaust pipe.The Cat may be fine, but there could be a blockage somewhere else.Keep us informed.

[zabone]

did you run over something?

[capelahave]

I have had the transmission checked by 3 mechanics and they all say it is ok. Where else could the exhust be plugged?

[capelahave]

No

[zabone]

a tune up would probably do the trick. maybe you have clogged spark plugs.

[Buzzman]

The traditional tune up is a thing of the past. That was a must do maybe 30 years ago, when we still had points, condensers and leaded gas. Not so today. I really don't think a "tune up" is going to fix his problem. Also, if the plugs were clogged (huh?), he would have issues at any speed.The only other thing that comes to mind is to check the fuel pressure. You may have a weak fuel pump. I had that problem on a Chrysler once. Van ran OK as long as the fuel demand was low. As soon as I wanted to get going, the fuel pump couldn't deliver enough gas, and the van would peter out. As far as the exhaust system goes, a collapsed pipe could be anywhere in the system. It's not easy to troubleshoot. When I have seen it though, it was usually pre-cat.Let us know how you make out.

[mgeldart]

Any Resolution on this yet?I have EXACTLY the same problem. Have had the fuel filter replaced, mechanic said it was clogged up but it did not fix the problem. Also it is intermittent, smacks of some type of sensor issue to me, perhaps a valve timing sensor?Any help would be appreciated. I will be having a dealership check the fuel pressure tomorrow.

Thanks,

[fueler]

try cleaning the MAF sensor with electrical connection cleaner. Its worth a shot and the symptoms match.

[Buzzman]

I was thinking some more about the clogged exhaust system thing. Your symptoms still sounds like someone shoved a potato or something in your tailpipe LOL. Seriously though, a broken down Catalytic converter can cause those types of problems too. If it starts to break down, then particles from the CAT can plug up your exhaust . Have someone rev up your engine and stand at the back with your hand on the tailpipe and see what kind of pressure you feel. It should be fairly significant.It may not be the problem, but it's one more thing to check, along with the MAF sensor and other tips in this thread.Good luck.

[Chris92SE]

try cleaning the MAF sensor with electrical connection cleaner. Its worth a shot and the symptoms match.

My QX4 seemed to lose power and it was pinging (especially uphills and on the throttle hard). It was the MAF sensor. However, it did throw a lean bank code and the CEL came on a couple of times. I replaced the MAF sensor and everything went back to normal, including the power.

I would maybe check again for codes. It is no fun trying to fix things by trial and error -- that gets expensive fast.

[MagicM]

By saying it " does not go any faster" do you mean nothing happens or it's just really slow to pass?. Because i used to own a 2001 pathfinder and the torque to pass at higher speeds 60-70 mpg with a 4 speed didn't exactly make it move that fast and took patience. Maybe the transmission is being Slow and trying to pass in overdrive, next time try and manually drop agear and see what happens.

[mgeldart]

I am at the shop, they say it is clogged CATs and they are doing a motor vac on it to try to un-clog them.

We will see......

I will update if this solves my issue.

[SnowSurfLax]

Never heard of unclogging a cat. Only option I've ever heard of is replacement.

Are they doing that for free? It seriously sounds like a scam to me.

[Buzzman]

Never heard of unclogging a cat. Only option I've ever heard of is replacement.

Are they doing that for free? It seriously sounds like a scam to me.

I have to agree with you on this one. If the CAT is clogged, then it's shot, period. It has to be replaced. I'd try another shop if I were you.Good luck.

[mobileprojects]

I have to go with Buzzman on that. I would check the fuel pump. I have that similar issue with a Chrysler Minivan. During the local trips to the store it was fine. When I needed it to accelerate to highway speeds or go up a hill, that's when it would back down.

Mobileprojects

[SnowSurfLax]

Yeah, might be a fuel pump just not having the gusto it used. You'd never notice until you were pushing it with higher RPM's.

How'd the CAT vac go?

[mgeldart]

Resolution found!! for my problem.

The Motor Vac did not fix the problem, and they never promised that it would, only that it was worth a try, low $$ compared to new cats.

Anyway, the problem was a stuck lower swirl valve. The dealership diagnosed the problem and they were able to fix it without replacing the valve.It's been two days and I just did 400 miles and it worked great.

[Buzzman]

Ok, so what the heck is a lower swirl valve?

[SnowSurfLax]

Ok, so what the heck is a lower swirl valve?

Ditto that.

[ianh]

Ditto that.

In the FSM it shows a dual butterfly valve that is in the intake runner. So closing this is like closing the throttle.

[astus]

I have been having this similar problem for months now. My mechanics just don't seemm to undertand it when I explain my loss of power
Can someone explain this Lower Swirl valve solution to me well so I can pass it on...am not enjoying my riide at all!

[rony024]

Hi
I'm using a 2005 r50 pathfinder, and recently I've been encountering the same issue wherein even if I accelerate just the revs go up and once i take my foot off the gas and accelerate slowly it gains speed . This does not happen frequently. So from my initial enquiry the mechanic says that it is the clutch issue or something related to the transmission. But after going through this post i feel it might not just be a gearbox issue.
What is the first thing to do in order to tackle the problem or better understand the problem?

[VStar650CL]

That may be a bad forward sprag clutch in the torque converter that's going full-slip when the trans tries to downshift, but grabs once you remove some of the load.