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Ted G.
Ted G., ASE Certified Technician
Category: Nissan
Satisfied Customers: 6089
Experience:  20 years auto repair experience, ASE Master Tech, Expert Witness
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Xterra: 2000 nissan xterra. starts up fine but rough idle with

Customer Question

2000 nissan xterra. starts up fine but rough idle with up and down rpms. right when i touch gas pedal, boom it dies. starts up fine again and putter/die putter/die while i make my way down the road. codes that showed up were o2 sensors, catalyst, knock, multiple random misfire, and a couple more. replaced the MAF, replaced the Distributor, nothing...
Submitted: 1 year ago.
Category: Nissan
Expert:  Ted G. replied 1 year ago.
You need to check the fuel pressure. It sounds like your fuel pressure is low. Do you know when the fuel filter was changed last?
Customer: replied 1 year ago.
no clue when it was changed last nor where on the car i could find it to change it? also recommended to me was a throttle position sensor. if i can somehow get the car driving then i will be going steady and then rpms drop,drop,drop, then catch again and rev back up to where it was
Expert:  Ted G. replied 1 year ago.
I would kind of doubt a TPS, but I never say never. It seems like you are "running out of gas" and then as the engine rpms come down the fuel kind of "catches up" and so it picks back up again. Fuel filter is right by the tank, if you are going to change it pull the fuel pump fuse and run the engine for a moment to drain off any pressure that might be there. It is a cheap thing to do as a first step.
Customer: replied 1 year ago.
ok i will try that first. i have almost half a tank of gas so how do i change the filter without having all of that gas go everywhere?
Expert:  Ted G. replied 1 year ago.
Once the pressure is off it won't leak out too much, but if you play golf, use a couple of tees to plug the lines as you pull them loose to keep spillage to a minimum.
Customer: replied 1 year ago.
ok i will try that right when i get home. if it was the fuel filter what would be causing the car to shake violently when idling and why the dying right when i touch the gas? also forgot to mention that i disconnected the MAF and it idled PERFECTLY for 3 minuted and then RIGHT when i plugged it in it died...
Expert:  Ted G. replied 1 year ago.
Well, if the fuel filter is clogged up, yes it could be starving for fuel at all times. When you unplug the MAF it goes to a rich mixture so it may have masked the loss of fuel pressure. It would be much easier to narrow down with a good scanner but let's get the basics first, do you have or can you borrow a high pressure fuel pressure gauge?
Customer: replied 1 year ago.
i dont have anyone with a pressure guage but a fuel filter should be a cheap enough fix for me to do it myself and not take it to a mechanic. i will try that right when i get off work. how do i get ahold of you from my personal computer at home once im there Ted?
Expert:  Ted G. replied 1 year ago.
Just sign back in with your username and password ***** any computer and come back to this thread. If I am not online ask your question and it will email me, I try to respond in a reasonable time (unless I'm getting my beauty sleep, which hasn't been working too well).
Customer: replied 1 year ago.
ok i need to make an account then. ill let you know after i change the filter how we're doing
Expert:  Ted G. replied 1 year ago.
Great, get back to me and we'll get through it. Some auto parts stores will lend/rent pressure gauges so if we need to that might be an option, but no sense checking till we get the filter on there.
Customer: replied 1 year ago.
Fuel filter changed. Nothing. When I'm idling, the harder I press down the faster it dies. If I let it just idle it will die in about 15 seconds. If I press down it dies almost immediately
Expert:  Ted G. replied 1 year ago.
Okay so let's see if we can verify it's losing fuel like I think. If you have a can of carb cleaner open up the air filter box and when it starts to die down spray the carb cleaner in the air tube into the engine. If the engine responds then you are losing fuel.
Customer: replied 1 year ago.
I don't have carb cleaner but how about wd40?
Customer: replied 1 year ago.
I hate to say it but I think the cats are clogged
Expert:  Ted G. replied 1 year ago.
WD might work, never tried that in a car. Have you been having a p0420 code in the past? Because usually cats will throw codes first. If you can get a hold of a vacuum gauge we can verify cats.
Customer: replied 1 year ago.
Yup definitely had the p0420 code as one of them
Expert:  Ted G. replied 1 year ago.
Well then you may be on to something. If you hook a vacuum gauge to manifold vacuum and try and rev it in neutral as the rpms go up, the vacuum will go down if the exhaust is clogged. But try the WD or Carb cleaner as a test if you can.
Customer: replied 1 year ago.
Okay so just take the filter off and spray into the tube when it's idling and listen for a kind of "rev"?
Expert:  Ted G. replied 1 year ago.
Yeah, you are supplying more fuel, so if the engine is starving for fuel it should perk up-WD is flammable so I am guessing it will work.
Customer: replied 1 year ago.
For the love of God I fixed it! Damn clogged air filter
Expert:  Ted G. replied 1 year ago.
Wow, that must have been one clogged air filter. Glad you got it, have to remember that one, never seen one that bad before.
Customer: replied 1 year ago.
I've never even heard of that causing 8 codes before. Unbelievable. When you told me to take off the air filter and spray into it I took it off and when I started the car it was perfect. I was like....that can't be possible
Expert:  Ted G. replied 1 year ago.
Yeah, that's pretty nuts. But they will run as long as they can until they just can't adjust any more then, nothing.
Customer: replied 1 year ago.
I completely understand how it could effect the motor that bad, but the fact that it could throw off that many codes really blew my mind. The motor literally has so much more power now that I can feel the power steering working better and 100% easier to turn the wheel Now we wait 50 miles to see if the check engine light stays off.
Expert:  Ted G. replied 1 year ago.
Yeah, you have to complete three drive cycles to make sure no codes reset. How did you replace the MAF and not notice the air filter?
Customer: replied 1 year ago.
The maf was on the outside of the hard plastic air filter case. So I just unscrewed it and screwed a new one on
Expert:  Ted G. replied 1 year ago.
Crazy. Well, glad you got it fixed.
Customer: replied 1 year ago.
Thank you! Now I'll know forever if a car is idling hard and dying. At least pull the air filter and try. That's easy and free to try compared to the $500 I've already tried
Expert:  Ted G. replied 1 year ago.
Yes, a few lessons cost more than others. Always look to the basics first, I help a lot of people here just by getting them to check the simple stuff first. But I get it, with all the computer gizmos, everyone thinks it just has to be that stuff. LOL.Have a good night!

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