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Jay
Jay, Nissan Technician
Category: Nissan
Satisfied Customers: 19874
Experience:  20+yrs experience with Nissan & Infiniti Trained & Certified.Currently still working for Dealer
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Before I take the car to the dealer I would give this a

Customer Question

Hi Roy,
So before I take the car to the dealer I would give this a shot. We are a non profit shop and we took in a donated 01 Xterra. It has strange symptoms. 1st. It will idle rough for about 20 seconds then will instantly smooth out for about maybe 10 seconds then go back to a rough idle. When driving it on the highway you can feel a slight misfire then it will just smooth out just like the idle. Sometime on low speed acceleration it will not accelerate for about 4 seconds then it will immediately "fix" itself and runs fine. When it does run fine it has plenty of power. So things we have tried. Spark plugs, wires, cap, rotor, distributor, MAF, injector cleaning(I saw a TSB on this being a possible cause) (fyi car came to us with a broken timing belt- so that is also new). When it arrived it had multiple misfire codes- cleared those and currently it is not throwing any codes.
Submitted: 1 year ago.
Category: Nissan
Expert:  Jay replied 1 year ago.

Hello my name is ***** ***** thank you for your question.

What brand spark plugs are installed in the truck?

Customer: replied 1 year ago.
I believe we put in autolite double plantnum.
Expert:  Jay replied 1 year ago.

These engines only like NGK's. Those plugs can be causing your problem. These engines were designed to use NGK plugs. Any other plug can cause misfire issues.

So lets change all the plugs to NGK Platinum Plugs and see if that resolves your issue.

Expert:  Jay replied 1 year ago.

If you have any more questions on this, please feel free to ask.

If not, and you're satisfied with my help, please Rate me. That is how I get credit for my work. I hope I have provided you with Excellent Service.

Thanks Jay!

Customer: replied 1 year ago.
Ok, I will try that tomorrow and will get back with you, but I will be really surprised if that fixes it. Especially since it comes and goes in a repetitive fashion.
Expert:  Jay replied 1 year ago.

Be prepared to be surprised.. You would not be the first that I have surprised by telling you this.

Customer: replied 1 year ago.
Looking forward to it :) I need to get this thing off my plate.
Expert:  Jay replied 1 year ago.

Well I look forward to hear back from you to hear how surprised you are...lol..

Expert:  Jay replied 1 year ago.

That is another question I answered where Autolites were used and NGK plugs resolved the issue. Just so you understand why I say to use the NGK plugs. I have seen this many times.

Customer: replied 1 year ago.
Unfortunately that link does not work. No worries. If you have a minute check out our webpage. www.scgarage.org.. This truck will be for sale to help fund the other ones we provide to low income families.
Expert:  Jay replied 1 year ago.

Not a problem. I am sure you will be happy with the results after changing the plugs.

https://dl.dropboxusercontent.com/u/105565483/1.jpg

Customer: replied 1 year ago.
Well unfortunately that did not fix the issue. There is really no difference at all. The issue is especially worse under light throttle on the highway and light acceleration around town. If you cause the trans to downshift it works fine.
Expert:  Jay replied 1 year ago.

Really.. I would have thought that was it. Did the truck have any major work done other than the tune up? Like a knock sensor or anything? Any codes?

Customer: replied 1 year ago.
We had the the timing belt done by a partner shop because it was broken when we received the truck. No codes yet. We do not know any history on it since it was donated to us.
Expert:  Jay replied 1 year ago.

Oh.. if you had a broken timing belt, you could be looking at some damaged valves causing the misfire. What you will need to do is have a cylinder leak down done to determine if there is any valves bent. When a timing belt breaks, 90% of the time it bends a valve.

Do you have any more questions on this?

Customer: replied 1 year ago.
I believe it runs too well to have a bent valve. Like I said it will cycle between running fine and misfiring and under mid to full load it has plenty of power. So I know you do not want to take a ton of time on this and are limited of what you can do via email.
Expert:  Jay replied 1 year ago.

I totally understand that. Trust me, I have seen it before. It runs great, but just has a little miss to it and it can sometimes come and go. It's because a valve is just slightly bent.

Expert:  Jay replied 1 year ago.

Are you a shop?

Customer: replied 1 year ago.
we are.
Expert:  Jay replied 1 year ago.

Do you have a Cylinder leak down tool? I can keep this question open so if you want to do a leak down on all 6 cylinders you can return and let me know the results.

Let me know..

Customer: replied 1 year ago.
We do not but I can inquire of some other shops that we deal with to see if they have one. Please do leave it open and I will let you know what I find.
Expert:  Jay replied 1 year ago.

You got it. I will keep this open and please keep me posted.

Customer: replied 1 year ago.
Hi Jay. I have some more information for you if you are still interested in helping. When I attached the scanner I see an issue with Bank 2. There are 3 readings that I see that are strange. 1 st the HO2S1 reads about .9 where as the HO2S2 hovers around 0.00. The Inj-B1 (msec) reads 3.4 where as the Inj-B2(msec) starts at 3.4 but goes up to 5.1. The higher it goes the rougher it runs. The A/F Alpha -B1 reads about 77 where as the A/F Alpha -B2 is fro 77-119. Again the higher it goes the rougher it gets. It runs through a cycle about every 20 seconds. Smooth to slowly running worse, then it self corrects and starts the cycle over.
Expert:  Jay replied 1 year ago.

It is hard tobgo by the readings with out seeing some of them live.

You are running rich. Did you replace the Maf sensor?

Customer: replied 1 year ago.
I did do the MAF. It is only the one bank that is running rich though. When I replaced the plugs with the NGK I did notice slightly more build up on Bank 2. So what controls one back over the other and why is the HO2 on the one bank reading close to 0
Expert:  Jay replied 1 year ago.

I wonder if you have the rear 02 sensor wires crossed.

See if you can follow the Passenger side rear 02 sensor to the connector and tell me what the harness side connector wire colors are?