Noises during throttle

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kirandb
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Joined: Thu Dec 08, 2016 11:17 am

Noises during throttle

Postby kirandb » Tue Dec 27, 2016 2:10 pm

This is related to 2006 pathfinder with 154 K miles on it. rebuilt tranny about 2000 miles ago. When the vehicle is in motion at constant speed, if i press the throttle slowly to increase the speed, i get a shuddering noises during which if i press the throttle hard, it dies of. this happens at different speeds from 20 mph to 80 mph. Not sure when to debug this issue from.
Just my thought is if i need to get any injector service done, not sure if they have something like that to clean the whole injector system. Any ideas ?

Thanks for your time.
Kiran


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smj999smj
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Postby smj999smj » Tue Dec 27, 2016 2:25 pm

This is tough without being to experience the problem myself. Have you checked for stored codes? Do you feel the shudder is a misfire? If so, how old are the spark plugs? A bad coil could do that or oil leaking into a spark plug well could do that as well, among other possibilities.

kirandb
Posts: 12
Joined: Thu Dec 08, 2016 11:17 am

Postby kirandb » Thu Dec 29, 2016 12:13 pm

As suggested by one of my mechanic friends, i got the injector cleaning service. The vibration noises seems to have died down and hopefully stays that way. For my service engine soon light, i was suggested to use catalytic converter cleaner in the fuel but the light is still on.
P0430 - is the error code. Not sure if it is the catalytic converter itself or the oxygen sensor. Is there a way to check if the sensor is bad if so which one (upstream or downstream)

Another thing i noticed is Autozone gives me error code P-0430 whereas advance auto parts & o'reilly's give me P0850 & P0430 error codes.
Which one is more accurate ? Have you ever experienced any such discrepancies ?

Thanks again for all the info.
Kiran

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smj999smj
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Postby smj999smj » Thu Dec 29, 2016 1:51 pm

Why one place pulled one code and the other, two codes, I cannot tell you. The P0420/P0430 codes are fairly common once these vehicles get some miles on them. Usually, an oxygen sensor will trigger a trouble code if it is faulty. The factory service manual provides some testing procedures for oxygen sensors, usually a component test to check resistance with the sensor and operation testing, which would require a scantool to view datastream info from the ECM. The upstream sensors are actually air/fuel ratio sensors, which look like oxygen sensors, but operate a bit different. The rear sensors are actually oxygen sensors and are only used for monitoring the upstream catalytic converter efficiency. More often than not, it is the upper catalytic converter that fails (becomes inefficient at breaking down the exhaust emissions) that triggers the code. I've had good luck with Walker direct-fit catalytic converters, but, in some states, converters need to be C.A.R.B. compliant to pass state emissions.

P0850 is not unheard of in these vehicles, as well, but is a less common code. It is for the PNP (park/neutral position) switch, which is part of the transmission's TCM/valve body assembly. The usually fix is replacing the TCM/Valve body assembly, which will probably fall in the $1500-$1800 range with parts and labor.


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