rnlock6185

I'm glad i found this site,would appreciate all the help i could get.I've changed spark plugs,pcv,had throttle body cleaned out,new air filter. I ran injector cleaner thru a couple of tanks full. Still idle's rough, gets even worse when i put it in gear. Runs fine after i'm on the road,and when i give it gas. Can a MAF be bad and not give a code to the computer,or does it sound like EGR problems. I put a lot of miles on this one 127,000. Would appreciate all the info i could get
rnlock6185

 

smj999smj

Well, I wouldn't suggest throwing parts on it without confirming they're bad. A rough idle can be caused by a number of differant things. Bad MAF's usually set a code, although the hotwire can become dusty and/or contaminated and cause incorrect readings and not throw a code. This is common when oil coated air filters are used like K&N. IMO, the best air filter for these engines is the one from Nissan. When was the last time the fuel filter was replaced?

Have you checked the distributor cap, rotor and ignition wires? One thing I learned over the years is that if you replace any of these items or the spark plugs, stick with genuine Nissan or NGK parts. Aftermarket parts tend to not work or last long on Asian ignition systems for whatever reason. Make sure the ignition timing is per specs.

You engine probably doesn't have an EGR valve. Models built 10/6/99 and later have no EGR system. It's referanced in bulletin #NTB00-012.

Early '00 models had some issues with idle fluctuation and bulletin #NTB00-007 addressed the problem. It pertained only to vehicles with manual transmissions and built prior to 5/17/99. The "fix" was an ECM upgrade and some adjustments.

Bulletin #NTB01-033a addressed rough idle due to dirty injectors. Tank additives don't always clean the injectors as well as a professional injection cleaning system, which runs the engine directly on the cleaner itself while the vehicle's fuel system is disabled.

Also, check for vacuum leaks. If you need copies of any of the bulletins, sens me an e-mail at smj999smj@hotmail.com and I'll get them out to you. Make sure you give me the year/model/engine/TSB# if requesting any.

If you suspect a dirty MAF hotwire, it can be cleaned with mass air sensor cleaner or electrical cleaner. I usually don't recommend it unless it's a last attempt before replacing the MAF sensor as the hotwire is very fragile. Break the hotwire and the sensor is toast!

If none of this helps, it would be best to get it to someone who has access to a scan tool that can view the datastream of the ECM. Nissan's Consult II is the best at doing this, but not the only option.

rnlock6185

Thanks so much for the info. I did replace the fuel filter as well as the other things i noted guess i forgot to add that. When i replaced the spark plugs i put autolite plugs in maybe i should i change them out again with ngk. I did go by autozone and had them to hook up the scan tool, only thing that came up was p0325 knock sensor. I didn't think that it was really the problem,judging by what the truck was doing. Will try to change out spark plug wires, distributor cap and rotors, or should i start with the professional cleaning of injectors first.

smj999smj

If the problem occured before the Autolites, then the spark plugs probably aren't the problem. Personally, I feel that NGK's are the best plug to put in it; they came with the truck originally from the factory and they are one of the best spark plugs on the market. Check the distributor cap and rotor and see if there's signs of arcing or the terminals are in poor condition. If they are original, I would definately suggest replacing them with genuine Nissan parts. Take a spray bottle and spray water on the ignition wires while running and note if there's any arcing; if so, replace the ignition wires. Personally, I prefer NGK ignition wires over the Nissan wires. Both are good, but the NGK's seem to be put together better although they can be hard to find in stock at most auto parts stores. You usually have to special order them or order them online. See how this works and then if you feel the injector cleaning is in order, go ahead.

By the way, timing belt is due on this engine at 105000 miles, if it hasn't been done, already.

rnlock6185

Thanks for the reply.Will try suggestions.I was looking at my truck today and it does have an egr valve, and the back pressure transducer. Could this have anything to do with what is going on. If it is stuck open would that cause the rough idle? I do appreciate all the help.

 

smj999smj

If it's stuck open, it will cause the engine to run lean....so, yes, it could cause a rough idle.

rnlock6185

Thanks for the info. You have been a big help.

rnlock6185

hey smj999smj,
would the ngk iradium plug be even better than the platnum tip that came from factory?

rnlock6185

In case anyone was wondering, Autolite spark plugs are crap!!! ecspecially for nissan's. Replaced them with NGK platnums. I learned my lesson. They made a world of difference no more rough idle or bucking. I've ordered new dist. cap, and plug wire set,as well as new rotor just to complete the tune up. Thank's for the help smj999smj.