Hey everyone, let me first say thanks to all who post and ask questions..... this forum has helped me out so much. Hopefully I get some more info here and it hepls someone else out.

So, I have a 2000 xj Sport with 154,000 on it. Have been doing some preventative maintenance and run into a few problems. Recently changed the injectors due to cracked boots and the fuel rail due to rust. Put in Standard motor injectors and a junkyard fuel rail without a dampener on it. Install went smooth and everything seated well, no leaks. Was driving it on the highway two days later the money light came on, P0174, lean conditions bank 2.

So far I have:
Replaced bank 2 O2 sensors (NTK), Coolant temp sensor, PCV, CCV, reset ECU and cleared codes then same code came back while at highway speeds for 15min

Then:
Replaced TPS, Coolant temp sensor, PCV, CCV
All three vacuum lines from intake manifold, brake booster (HPI motorsport silicone set)
Spark Plugs (NTK)
Reset ECU

I have only driven it around town for about 30min since and what I am seeing now is that once it enters closed loop it runs rough at idle when in gear. I will take my foot off the gas when comming to a light and when the car downshifts into 1st gear the rpm's drop to about 500 and car begins to shake a little like it wants to die, but never does. At speed it runs "perfect" and in park or neutral it does not get choppy.

I have cleaned the throttle body and IAC still to no evail. Fuel pressure is 49PSI at about 1500 and 46 to 49 at idle. The P0174 code has not come back but the rig is definately not back to what it was before I did "preventative" maintenance. Any suggestions of comment would be of great assistance. Im afraid I done have STFT or LTFT data.
Thanks in advance.
~W

Cylinder 1 on left, 6 on right
Yes the gaps were bad lol

 

Must jave been somthing I said

 

Odd code. Bank 2 means the side of the engine that does not have #1 spark plug. In other words, it's a code for a V-Type engine, not an inline engine.

On my 98 I had a very poor idle and two things were at fault. First, the idle air controller was shot. Some people mention cleaning them but mine was so corroded and gunked up I just replaced it. That thing has a stepper motor function and it had to be shot because even if badly gunked up a good stepper motor would make a noticeable change to the idle. Mine didn't. I changed it and got the cold idle back. Then, the front O2 sensor gave me a poor hot idle.I replaced that and got the hot idle back.

Rule of thumb, at 100K miles replace the manifold O2 sensor, minimally.

 

Fuel trim numbers and code reader would help a lot. I suspect your new injectors. Put the old ones back in and see what happens. If you had the STFT and LTFT this would probably show your new injectors running too rich, I am guessing to due to the lack of info. Also, did you really have a PVC valve on your 2000 4.0?

 

So for an update, 97grand4.0 you were correct. Although my new injectors were good, two of them were not seated correctly. After days of messing around and cleaning sensors I stood on the DS while engine running and hood up reving the motor. I had listened for hissing sounds a few times previously (thinking vacuum leaks) and this time heard a VERY faint whistle/sucking sound. It took me a few minutes to locate it, was waving my hand around the fuel rail listening for changes in pitch. Pinpointed the sound at the third injector. No fuel leaks and no apparent crimped or unseated o-ring, just the sound. Pulled the fuel rail.... again.... and did an extra thorough job cleaning the injector ports. Noticed a small tear on the #1 injector o-ring, however, the #3 o-ring looked ok (maybe just not seated completely). Replaced both o-rings, LUBED them and the ports REALLYYY well. Running like a boss now.

Air being taken into the #3 cylinder causing rich fuel trim and thus P0174. Thanks for the ideas fellas.
Fixed

 

Outstanding, always great to hear what the outcome was, it helps all who read this. Makes sense since the code was for lean. Thanks for letting us know.

 

Having a very similar issue.... still revving as though it's getting no gas (or too much?), stalling, and dying in park, reverse, or drive. If it starts to do it while going up to a red light, I'll just throw it in neutral and that stops the issue. I'll put it back in drive and it starts back up again. Within last few weeks, i replaced the rear O2 sensor and replaced to TPS. Thought it was fixed, but alas.... I replaced a bunch of corroding vacuum tubes 6 months ago. I switched out the spark plugs maybe 2 years ago but don't recall if the issue started before or after the spark plug switch... I'm guessing not... Would love some guidance. Thanks!

 

Maybe move this to a new thread instead of hijacking this one?

 

Its all good, this thread was finished but you might not get alot of ppl commenting if you keep it here. Considering I just went through this nonsense....

1. Pull your plugs and see how your gaps are, 2 years is not that long but they are easy to pull and will tell you a lot about whats going on inside your engine.
2. Clean or replace your Idle Air Control valve, super easy and if it is the problem you will be able to tell after douching it up.
3. Clean or change your air filter
4. You said you replaced vacuum lines? get under the hood and listen for and whistles, the only one you should hear is inside your throttle body.

Its either an air or fuel issue. No codes?