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Discussion Starter #1
Hello B15! I’m new here but have been reading up on some threads regarding power loss on the B15’s. I’m sorry in advance if this isn’t the correct thread. Mine is an 03 with 166,300 on the clock. Recently I have been having issues with intermittent power loss on acceleration and hard starting. Sometimes it fires right up and has no issues when driving, and sometimes it struggles to start and will have a hugely noticeable decrease in power, to where it will be really high in the rev range when the accelerator pedal is fully on the floor and the car barely accelerates. When it’s functioning “normally” the car has much better acceleration. I do have a code, P1138 which is for the swirl control valve on the intake manifold, however that code has been around for quite some time and never seemed to have any issues. I had it taken to a family member who owns a shop, he cleaned out the fuel rail and the code went away for long enough to pass smog, however when it did come back it never gave me any power issues. I checked the battery and alternator, both were reading 14v when running and the battery was about 13.6 when off I believe. Yesterday I replaced the fuel pump unit since I suspected the fuel filter was clogged and it’s all one unit, which immediately resolved the hard starts and for the 10 miles I drove it to get a fuel system cleaner and filled up the tank. This morning it started up like a charm, with temps being down in the high 20’s Fahrenheit, however it immediately had the same power issues until I restarted it about 2-3 times. Any information would be greatly appreciated!
 

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Discussion Starter #3
Doh, how did I not think of that? I’ll pick up some MAF cleaner and report back later. Is this the correct section of the forum by chance?
 

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Discussion Starter #5
Went ahead and cleaned the MAF as tell as the TB(which was pretty caked in soot, as well as the upper intake manifold) and put it all back together. Took it for a drive around the block and it seemed to be okay. However this morning after starting it and letting it idle for about 5 minutes to warm up the car and defrost the windows, it immediately had same power loss as stated earlier. The only remedy was to park the car and restart it about 4-5 times on my way to work. I noticed that when I went to clear the P1138 code, the swirl control valve would try to actuate, but wouldn’t move and the linkage on the driver side of the intake manifold would just vibrate since it’s loose. I feel like it might be the swirl valve finally causing the issue, however I wanted to get some insight before plunging 400$ ($80 on eBay used) on a new intake!
 

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Discussion Starter #7
Yeah I checked it about 3 times last night and it was always P1138 and anytime I would clear it, it would come back in the pending codes and this morning the check engine light came back on. When I googled it(I don’t have a FSM) it came back with a Swirl Control Valve open or short, however I’m not sure how I would go about testing the harness to make sure it’s working.
 

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I did a search and I forgot they had like 2/3 different 1.8 variants with yours being an SULEV for that year.

Assuming the harness and the swirl valve is good, it could be the sensor for ther valve, see if they sell the sensor separately.
 

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Discussion Starter #9
I did a search and I forgot they had like 2/3 different 1.8 variants with yours being an SULEV for that year.

Assuming the harness and the swirl valve is good, it could be the sensor for ther valve, see if they sell the sensor separately.
Pretty sure the issue is related to the valve since, whenever having the power loss, I can clear the code and restart the car and it goes back to normal. The manifolds on Ebay don't appear to have that valve in the lower portion, I wonder if I could install another QG18 manifold over? Would probably need some modification/replacement of the ECU though :unsure:
 

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Everything is picked up by the sensor, if that sensor is bad and the valve is activating properly the sensor isn't going to know... the sensor is in the trouble shooting steps for that code in the FSM and unless you are checking voltage first I wouldn't replace the swirl valve just yet.
 

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Discussion Starter #11
Everything is picked up by the sensor, if that sensor is bad and the valve is activating properly the sensor isn't going to know... the sensor is in the trouble shooting steps for that code in the FSM and unless you are checking voltage first I wouldn't replace the swirl valve just yet.
Do you know how to go about testing voltage? I have a voltmeter, I just don’t know how to go about actuating that valve/sensor to see what’s going on. You wouldn’t happen to have any part numbers on the sensor would you? I’ve looked everywhere and can only find a similar looking one for a 2003 Pathfinder😟
 

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Download the FSM, if you can't find it I'll link you but it will just be easier that way cause that's all I would be doing is posting screenshots of it for that section.
 
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