# Vehicle Losing Power while Consistent on the Gas



## Alin99 (Aug 3, 2005)

Hello,

Our 2006 Murano has started developing a strange issue where if the gas is pressed lightly and steadily, it momentarily loses power and acts dead. After the moment "of weakness", power returns and the vehicle continues on normally. While this is happening, I have noticed that the rpm drops to idle. This "jolt" of power loss is substantially stronger than just letting go of the gas and letting the vehicle cruise..

Does anyone know what might be going on? There is no check engine light. 

Thank you,


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## rogoman (Dec 16, 2004)

Alin99 said:


> Hello,
> 
> Our 2006 Murano has started developing a strange issue where if the gas is pressed lightly and steadily, it momentarily loses power and acts dead. After the moment "of weakness", power returns and the vehicle continues on normally. While this is happening, I have noticed that the rpm drops to idle. This "jolt" of power loss is substantially stronger than just letting go of the gas and letting the vehicle cruise..
> 
> ...


What's occurring appears to be a misfire on one or more cylinders.
Several things that could cause misfires:

A common problem with random engine shutdowns, difficult startups, rough running is a marginal camshaft position sensor or a marginal crankshaft position sensor. Most of the time when this happens, the "check engine light" never comes on; subsequently when performing an ECU code readout, there was no fault code set.
Incorrect fuel pressure. Tee-in a temporary fuel pressure gauge between the fuel feed hose and the fuel rail. The reading at idle should be 51 psi.
There may be a major intake system vacuum leak. To check the intake system for a vacuum leak, attach a vacuum gauge to a full vacuum source. With the engine fully warmed up, the reading at idle should be 18 - 20 InHg. At 3,000 RPM, it should be 21 InHg. If readings are under 18 InHg, check the intake manifold nuts to make sure they are tight. The gasket may have failed; spray a water mist at the gasket to see if the gauge reading changes. Also check the intake plenum bellows at the throttle valve and at the MAF for cracks or loose clamps.
Dirty fuel injector(s). Run some good injection cleaner, like BG products 44K, through the system; give the cleaner about a week or two to do it's job.


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## VStar650CL (Nov 12, 2020)

First thing, check for a bug in the MAF. It's a dumb problem and easy to clean out. Unlike other brands that have a MAP sensor to let the ECM double-check the MAF, most Nissan ECM's are totally dependent on an accurate MAF reading. So all it takes is a piece of stray lint or butterfly wing to completely screw up your engine performance.


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## Alin99 (Aug 3, 2005)

Hey guys, thank you for responding.

Rogoman, a year and a bit ago the Murano started experiencing random misfires and I (along with a shop for the back sparkplugs 😆), replaced all 6 sparkplug with oem premiums. The problem still happened and I diagnosed the issue to one of the spark plug coils. I replaced it and the vehicle hasn't had an obvious misfire since.. could it be another coil? I will buy some injector cleaner and try this ASAP.

Vstar650cl, I tried cleaning the MAF last night. I don't know if it worked, we'll find out within a few days-maybe?

As winter has returned to Alberta, I can't do too much else until it warms up..

Alin


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## VStar650CL (Nov 12, 2020)

davidjohn35650 said:


> A clogged fuel filter is the most common reason


_There is no fuel filter on a Murano._ The only filtration is a screen in the fuel pump.


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