Power issue

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Stevenoskoskavi
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Power issue

Postby Stevenoskoskavi » Wed Jul 10, 2019 12:55 pm

Howdy all! Here to pick some brains. I have a 2004 Pathfinder 4wd 3.5 V6 with some power issues. Under full throttle conditions the acceleration is slow and seems to hesitate. If I back off to around 50% throttle, it picks up much better. Also, after driving and shutting the vehicle off, When I start it again it doesn’t not fire immediately and acts like it’s missing. Once it does start, It will sit there and idle rough for about 8 to 10 seconds and then the idle will bump up and smooth out. On very rare occasions, It will lose power and not want to accelerate at all. Fuel filter and cam position sensor has been replaced. No codes pertaining to ignition faults. Fuel pump seems in working order but I have not tested the pressure. Any information would be more than welcomed. Thank you!!

-Steve


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Postby Heavy hitter » Wed Jul 10, 2019 7:28 pm

Sounds like possibly a mag issue. Try cleaning it with maf cleaner. You don’t possibly have a high flow oilable air filter on there do you?

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smj999smj
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Postby smj999smj » Wed Jul 10, 2019 7:46 pm

It could be oil in one or more of the spark plug wells, creating a misfire between the tube and the coil boot. It could be a failing coiling, which don't always trigger codes, or badly worn spark plugs. It could also be a a bad fuel injector or low fuel pressure.

Stevenoskoskavi
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Postby Stevenoskoskavi » Thu Jul 11, 2019 3:56 am

Spark plugs and valve cover gaskets were changed about 1500 miles ago. Problem still persists. I do have a K&N air filter which I put in after the plug and gasket change. I will give the MAF a good cleaning and test fuel pressure and see what she’s doing. Thanks for the Info gents!! I will keep you posted!

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smj999smj
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Postby smj999smj » Thu Jul 11, 2019 8:11 pm

Valve cover gaskets won't keep oil from going into the spark plugs wells; that's controlled by the spark plug tube seals. So, unless you replaced the valve covers, themselves, you can't completely rule out the possibility of oil leaking into the well unless you pull the coil packs out. Another possibility is a fuel injector leaking down, which could cause a hard start and foul a plug, which would burn off as you drive it. A fuel pressure leakdown test would confirm that. A bad crank position sensor would also affect startability and could creat misfire issues. So, it may not be just one problem and you may have to do some diagnostic work to figure out what problem, or problems, exist. Cleaning the MAF is a good start. Make sure your battery connections are clean and tight. Check for any potential air leaks, like splits in the rubber intake duct or split/disconnected vacuum hoses. Check the fuel pressure. Keep in mind you have more than one cam sensor. Also, a ignition coil pack could be failing and may not be triggering a code, which could create the symptoms you have.

Stevenoskoskavi
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Postby Stevenoskoskavi » Tue Jul 16, 2019 4:02 am

I’ll give that a go as well. The battery connections are good although I tend to clean the negative terminal quite a bit. It corrodes. A lot. The Interweb is telling me that’s an indicator of an undercharging system. Checked that and was producing around 14.1v so I’m thinkin the battery might be going bad. I’ll run through it but will probably let her ride as funds are tight. Still runs good for not running a 100%!

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palmerwmd
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Postby palmerwmd » Tue Jul 16, 2019 8:34 am

Did the K&N filter come prior to the loss of power?
Nissan MAFS hate K&N filters as they dont tolerate the oil that always seems to come off them

Stevenoskoskavi
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Postby Stevenoskoskavi » Tue Jul 16, 2019 11:11 am

The K&N came after. This thing has had a power issue since I bought it. The issue has not worsened. The only time there was an improvement was when the fuel filter was replaced. I’m going to pull the fuel pump this weekend and check out the tank and screen. I’ll be sure to smoke a cigarette when doing so.

Stevenoskoskavi
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Postby Stevenoskoskavi » Tue Jul 23, 2019 3:44 am

Looked at the MAF and it’s very clean. Pulled the fuel pump and the screen was clean and tank was spotless. I will do a fuel pressure test one of these days. I still average about 16mpg (mostly city driving) even with a O2 code so I reckon I’m in alright shape.

Stevenoskoskavi
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Update!!!

Postby Stevenoskoskavi » Wed Nov 20, 2019 2:17 pm

Well it took me long enough. After taking my pathy to the stealership, they couldn’t find out the issue regarding power loss under full throttle conditions. They were not helpful what so ever but the had no issue letting me pay them.

SO...I have a friend with a nice Snap-on OBD reader that was able to give me an active read out on everything. The only thing that was off was the ECT. It was reading at 221* even though the vehicle was at normal operating temp. I read on another forum that the timing gets pulled quite a bit when above 200*. I’m really hopping this is the issue.

Sensor was $22 at NAPA and intanke gasket kit was $35ish at Advanced. The only issue with changing the sensor is that it is located on the coolant crossover on the back of the engine. This means, to do it in a manner that isn’t more frustrating than the DMV, I have to remove the intake. May take longer but at least I won’t have to fight my way through it. While I’m at it, going to throw a fresh coat of aluminum paint on the intake because I like a good looking and clean engine bay.

Will provide update once the repair has been made.

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palmerwmd
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Postby palmerwmd » Thu Nov 21, 2019 10:04 am

Steven, thanks for the update!

Sorry we couldnt be more helpful but diagnosing such things over the internet is difficult unless its a typical know issue associated with a model year..

Stevenoskoskavi
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Postby Stevenoskoskavi » Sat Nov 23, 2019 7:15 am

No need for apologies. You guys helped me eliminate many possible culprits.

Update:

After the instal, there was a noticeable change in the power but the issue still remains. Under full throttle, there is still hesitation. I will hook the OBD reader up again and see what the temp is reading now. Like usual, my diagnosis was wrong and I’m chasing a mirage. Up side to this was I was able to throw a fresh coat of aluminum cast paint on the intake so it looks nice and clean. Will keep you guys posted!!

Stevenoskoskavi
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Thinking maybe it’s the fuel pump

Postby Stevenoskoskavi » Sun Jan 19, 2020 6:55 am

So, after over a year now...after replacing the exhaust, a cat, intake plenum gaskets, thermostat, vacuum lines, VVT solenoids, cam position sensor, both Evap solenoids, gas cap, and the fuel filter......think the issue is a weak and failing fuel pump. Ordered a new one so I will see how that goes. Hopefully it’s not another part added to the list.

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palmerwmd
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Re: Thinking maybe it’s the fuel pump

Postby palmerwmd » Sun Jan 19, 2020 11:12 am

Stevenoskoskavi wrote:So, after over a year now...after replacing the exhaust, a cat, intake plenum gaskets, thermostat, vacuum lines, VVT solenoids, cam position sensor, both Evap solenoids, gas cap, and the fuel filter......think the issue is a weak and failing fuel pump. Ordered a new one so I will see how that goes. Hopefully it’s not another part added to the list.
Wow! :shock:

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smj999smj
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Postby smj999smj » Sun Jan 19, 2020 11:36 pm

Well, I did tell you to check the fuel pressure back in July. If you haven't checked it, still, I would recommend you check it before replacing the fuel pump, otherwise you may end up dumping more money down the drain. Checking fuel pressure is cheap....fuel pumps are not! :wink:


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