Hi guys....

Another problem that I can't seem to fix on my own.

Due to the above code, I went and changed:

3-O2 sensors changed...

PCValve changed but ordered a new onefrom the dealer) hasn't arrived yet.

Spark plugs were changed with Fuel filter/PC valve...

This code tells me:
Intake leak failing front heated with oxygen sensor
Faulty fron heated O2 sensor
Ignition misfiring
Faulty fuel injector
Exhause gas leaks
Incorrect fuel pressure
Lack of fuel
Faulty MAF sensor
Incorrect positive crankcase ventilation (PCV) hose connection...


When I warm up in the morning...idle is low, wheel trembles (not much but a tremble is there)
As I drive the RPM seems to stick and idles high...at a stop does it as well
I bought a new Idle Air Control valve..thinking that would solve my problem...

I also ordered the correct PCV from the dealer due to code given..That I haven't replaced as yet...

If anyone had this problem or similar and was able to correct it, I need advice..I'm ready to put the damn car up in flames for this little problem that is driving me wild...any suggestions would be greatly appreciated..

My next step is to just take it to a mechanic and let them start where I left off...

TIA

 

Sounds like an IM leak since it's only happening at idle.

 

what is a IM leak mean?

 

You shouldn't be replacing o2's due to a lean code. That's actually the last item you should look at. The lean code means something isn't right with your a/f. You still have more troubleshooting to do.

 

I have a mechanic around the corner from me who ran a diagnostic on the vehicle...Simple problem...solved...the IACV has an adjuster on the back of it...it was open so too much air was flowing through it and not enough fuel. He closed the idle adjuster that sits on the IACV itself, no more erratic idle..he also sprayed the engine with water to see if there truly was a leak...no leak detected. Engine remained running as it was supposed to as long as there were no leaks detected..

The other problem is due to my buying the aftermarket O2 sensors..two front need to be replaced with the original parts from Nissan..trying to get over cheap, doesn't work out well...I now need to order those sensors from the dealer...All is okay for now, until I get those sensors from the dealer..

 

1) IACV provides air to both banks via the upper intake. Doesn't make sense that only one bank would come up lean. He may have set your idle speed correct, but your lean condition is most likely going to resurface as you drive and the ECU goes into open loop mode, measuring a/f under set load conditions.

2) Nissan doesn't make 02 sensors, they build cars.

Define an "Aftermarket" o2 sensor? They all work the same and are only made by 2 or 3 companys, Nissan NOT being one of them. Which brand did you use?

Did your mechanic look at fuel pressure?
Did he check for a clogged fuel injector?
Did he look at the a/f in real time with a scanner to see what the o2's are reporting?
Did he check the MAF signal?

Spraying water on the engine is not the way to locate an intake leak.
It does help find ignition wire problems (which we don't have on the VQ). You need to use a carb cleaner or other combustable solution to find an intake leak which shows it's source when the engine speed increases as you spray into the area where the leak is. Last time I checked, water isn't flammable...

3) Maybe find another mechanic?

 

The idle was a separate issue along with other issues that came up...

Bosch...made those sensors but am told the orginal from nissan is better..when I changed to these sensors (aftermarket), that is when the car started acting up. So whatever Nissan parts are, or who makes them, the car runs better with original parts...not aftermarket parts for the O2 sensors, anyway...

He sprayed with carb cleaner first...so I don't think he was that far off..

Finally the idle is corrected. It was from the IACV which has an adjuster on the back of it, was open and should remain closed...so my vehicle was getting more air than gas..

As of now, my idle isn't erratic, runs smooth, great p/u, so I take what this guy did as he is a good mechanic...I should have went to him straight off...

I do thank you for your input. I realize it's hard to diagnose something when it's not right in front of you...

Thank you for your input.

 

Make sure there is no air leaks. I had an air leak where the IM connects to the top tube of the EGR. This leak caused P0174 on my max.

 

Heys guys,
I am dealing with the same problem and code. How would I know if there was an air leak. Is this something I can do without a mech? Just trying to get my baby working right b4 I start posting pics of it lol lol.

Thanks