Hello All,
I have an 03 X type with 140K miles on it. I am receiving a P171 and P174 codes on the car, took it to mechanic to run a Diagnostics on it and it said bank 1 and Bank 2 Lean. I've read many other posts on here that were directing me in 20 directions so I decided to post to see if I could get any answers.
I've replaced the IMT seals, the brake booster, all the spark plugs and its seals, the MAF sensor has been cleaned, and the vacuum hose has been replaced. So after doing all this work myself, the car still gives me the codes!!
So can someone please point me in the right direction and let me know what else it possibly can be??? Im wondering if it may be the fuel filter, but I dont want to go buy it, replace it, and have those darn codes still!

 

Loyal, it sounds like to me you have a leak in your intake tubing between the air box and the throttlebody. Specifically I would do a good once over of the accordian section as this is the most likely place to get a rip in. After that, it may be possible that the MAF sensor is bad.

 

Thermo, I checked over the accordion and replaced the MAF sensor, and unfortunately only got rid of the P0174 code. The P0171 code still comes up and it said "Bank 1 Too Lean". This is frustrating but i'm trying to keep my cool. Any other suggestions anyone??

 

I had same exact codes on my dad's car , not just but logic is same . They replaced the following parts and no more idiot codes since then

EGR Valve
PCV Hose
MAF cleaned
plus ,O2 sensors could be culprit too

 

I have the same codes. No jag dealers near me. They place said they could start in the book and doing it what it said and go from there...I passed...ha I hoping it's nothing too serious. It's been about a year and my car has 192k miles.

 

Loyal, now that you re down to only the P0171 code, you need to be looking specifically at the top half of the intake. This is going to be the area where you are likely going to have issues. To ask a silly question, when you replaced the brake booster hose, did you replace the little plastic piece in the intake manifold that holds the assembly in place? It may be possible that the little retaining clip that is there is starting to go and it is not holding the brake booster line solidly enough. It may also be possible that when you did the IMT valves, the o-ring shifted as you put it in. So, take a look at the upper IMT valve. After that, I am at a loss. Those are the only 2 ports that are on the intake that would only affect the one side of the engine. The only other possibility would be a bad gasket between the upper and lower half of the intake or the gaskets between the intake and the head is bad. Unfortunately, if you are going in for the upper gasket set, might as well go a little deeper and do the lowers too.

 

Like Thermo said about the booster pipe, the plastic could be brittle. Under that plastic though is a nice little o-ring. At your mileage i would nearly guarantee that thing is rock hard and not sealing very well. there are two on top. one for the booster and one for the purge valve. replace the orings and plastic clips and clear your fault codes and you should be good to go barring any other uncommon problems. MAF sensors do go bad in those cars but do the easy stuff first.

 

Thermo & BlackX,
What seals are we Talking about? I went to both the brake booster and purge valve and only see the plastic that's inside the manifold itself. Those things are rock hard, but don't seem to be letting any air out. Can those possibly be the culprits and reason why I'm still getting those codes?? I literally ripped apart everything today and all the seals were good. My last place to look at are the O2 sensors. But my code reader tells me that the O2 sensors are good, so I'm confused. Thanks for your help so far, I truly appreciate it.

 

Loyal, get a can of starter fluid and give a spray on the brake booster hose connection to the intake, the IMT valve o-ring groove, and any other inlet to the intake. Where you hear the engine RPM pick up is where the vacuum leak is. If you don't find a leak this way, then odds are you are looking at the intake gaskets (both uppers and lowers to be safe and only having to go in 1 time to fix the problem, besides, the gaskets are cheap).

 

I opted to have a smoke test ran on my car after the starter fluid test in my garage didn't lead any results. It's amazing how well the smoke test works, pointed out all the leaking seals... wow.

I shopped around a little and found that Tunex does the smoke test for a flat rate of $49 Not bad.

I then found another link on this site that directed me to www.partstrain.com where I got all twelve seals (upper and lower) for a ridiculous price, added spark plugs to my order and for $60 in parts I'll be doing it in the garage as soon as they arrive.

If you are a do it yourself-er, get a smoke test done and you'll have your vacuum leak problem solved in no time.

 

What is that Tunex place? I live in FL

 

I think those are my code culprits, Would you have the parts numbers? I could not find the part numbers for the tiny o-rings. Thanks!

 

97 XK8. After searching for vaccum leaks in all the suggested places with no success I finally found it. First, a little background. The car was running rough at idle but ok ( not great) ]at speed. Had frequent engine fault/ reduced performance and check engine light on. I could hear a hissing sound near the front, sprayed carb cleaner there and the idle picked up immediately. There is a plastic 4 inch plate covering a hole in the front of the intake manifold. Right behind the coolant cap. It is just glued on with something like JB weld. Given the age, miles, and heat,the seal had failed and had developed a gap in the bottom. I picked and cleaned the mating surfaces and sealed it with polyurethane caulk. I wedged a thick washer between it and the coolant housing to hold it.No more lights, purrrring like a kitten!

 

I don't know the part numbers but it comes as a small kit from Jag. It includes a brass insert (throw away), a plastic chinese fingers, and a new o-ring. Use the new plastic pieces and o-ring.

 

go to my thread (MY X-TYPE PROJECTS AND INSTALLS) I HAVE PICS AND A WRITE AND A LIST OF ALL THE CODES DEFINITIONS...MY THREAD IS A LITTLE LONG AND JUMBLY BUT YOU WILL FIND WHAT YOUR LOOKING FOR

 

I get the same codes but when it gets warm they go away. I had them appear last winter too and once it warmed up they went away. It is annoying because it will not let you go above 3000 rpm. I do not want to go through all of the replacement of sensors, gaskets etc. for no apparent reason.

 

I had the same problem and found that my lower intake gasket was porous i changed all the upper and lower intake gaskets and that did it. BTW...change the gasket by the oil cap, mine was also leaking.