Here is what it does. .. when it's cold, itr barely runs. When it warms up, it runs fine, unless I'm sitting at traffic lights, in which case, it won't rev over 3000 rpms. After a few minutes, it runs fine again.

Here is the list of stuff that has been replaced already:

Throttle position sensor
Plugs
Coils
Manifold seals at cylinders
IMT seals
Brake hose
EGR hose

And oxygen sensors.

The code reader said o2 sensors air 140 miles after they were replaced when the check engine light came on again.

What is next in my list of stuff to replace?

 

Post the actual code(s).

Check fuel trims (LTFTs). Engine hot, parked. At idle & about 2500rpm.

I suspect an elm327 will work on your car and they're cheap & good.

 

0171
0174

They're saying MAF sensor... im going to replace that and see what happens. ..

 

That's usually associated with vacuum leaks. Seeing as it looks like you replaced the usual IMT O-rings, brake booster and PCV hose maybe check the accordion hose between the MAF and the throttle body to make sure it is tight or maybe have a split in it. Or do the starter fluid or cigar test to see if you can see where there might be an air leak.

 

Do the rest of post #2...

 

I ordered an elm327, once it comes in, I'll hook it up and we'll see what it says.

 

ok, got the elm27, here's what it says...

edited... with codes

P0171 system too lean bank 1
P0174 system too lean bank 2
P0138 O2 sensor circuit high voltage
P0158 O2 sensor circuit high voltage
P1000 diagnistic trouble code

I cleared out the codes, the car immediately began running better.

 

See if codes come back. Meanwhile follow post #2. Starting to sound like an echo...

 

short term fuel trims are all over the place- they can be at 25, -25, 8, -8, 0, -1.... All in a 10 second period.

recurring error codes are the too lean codes, the oxygen sensor codes, occasionally I'll get a misfire on all 6 cylinders (it's all or nothing with this car!)

 

Tumbleweed: Just spitballing...... Try replacing the PCV valve if it's old. It's a $15, 5 minute fix: PCV Valve Standard V516 Fits 02 08 Jaguar x Type 3 0L V6 | eBay

When you replaced the manifold gaskets & IMT O-rings, did you see engine oil puddled inside the manifold and dripping from the manifold gaskets? An old PCV valve can stay open too long, allowing too much crankcase air into the intake manifold, causing a lean condition. The excess crankcase air also aspirates engine oil into the manifold. The PCV valve & hose are supposed to suck a little crankcase air into the manifold, to prevent oil fumes and ring blow-by from become air pollution. But too much crankcase air into the manifold can create a lean condition (problem) and puddles of oil in the manifold (not a problem, but an indicator of a failing PCV valve, unless it's so bad that you start losing / burning oil).

This helpful site has more info on PCV valves: AGCO Automotive Repair Service - Baton Rouge, LA - Detailed Auto Topics - What are the Symptoms of a Bad PCV Valve

 

The latest update. . Replaced the PCV valve, and it runs 1000% better.

Trouble is, I'm still getting too lean on both banks code.
It's also saying sensor 2 on bank 2 is faulty, and sensor two on bank 1 doesn't report half the time.

Apparently, my mechanic only replaced two of the four O2 sensors, so that is being rectified on Tuesday.

Car had 94k miles when I bought it 4 years ago, it has 185k now.

 

Tumbleweed: Glad to hear your engine's running much better with a new PCV valve. The old valve just have stuck open, allowing too much crankcase air into the intake, causing the lean condition.

Did you clear the error codes after replacing the PCV valve? If 'no', the lean codes may be 'old data' from the old PCV valve. When your mechanic replaces the downstream sensors (aka sensor 2), have him clear the codes, or do if yourself if you have a code reader.

The ECU will re-learn how to adjust engine conditions for the new PCV valve, downstream sensors, etc. To speed the process, with everything off, i.e., the key removed from the ignition, disconnect the positive cable from the battery and touch it to the negative battery post. After reconnecting the positive cable to the battery, drive as you normally would and the ECU will relearn to control engine conditions for your driving style with the new parts installed. If you do this, you'll need to reset the clock, and the one-touch feature on the windows & sunroof. Also, the trip odometer will reset. It's not required, but helps the ECU re-learn more quickly.

185K miles is impressive. You're doing something right!

 

another quick update.. .things move slowly around here... lol

All the O2 sensors have been replaced, finally, along with the fuel filter. It runs much better, but is still sluggish when first started in the morning, and I still get all sorts of error codes, mainly too lean on both banks, and occasional misfires.

I'm going to replace the accordian hose at my next convenience, are there any other hoses that can cause a vacuum leak?

 

You may find this more helpful and cheaper

 

Tumbleweed: Use your ELM327 to confirm you have a vacuum leak, by checking the long term fuel trim at idle and at ~2,500 RPM. With the engine hot, the scanner plugged in and the transmission in park, check the long term fuel trim on both banks. It's probably above 10% because we think you have a vacuum leak. Now with your foot on the gas pedal, hold the RPM steady at ~2,500 for ~30 seconds. Did the long term fuel trim drop to less than half, e.g., from 10+% to ~5%? If yes, you have a vacuum leak in the intake manifold. This test is what JagV8 suggested a few times above.

A few ways to find the vacuum leak:
1) Smoke test, as PaulC732 suggests
2) Inspect the 5 common leaks, described in these posts:

https://www.jaguarforums.com/forum/x...1/#post1309725

https://www.jaguarforums.com/forum/x...1/#post1357803

3) Carefully spray carb cleaner, starter fluid or propane gas around the intake manifold near the likely leaks until you hear the idle noticeably change. When it does, watch for the fuel trim readings to jump around (because you're adding fuel to air leaking into the intake). Just be very careful if you try this: hot engine + external fuel = fire in the engine bay. So be sensible: fire extinguisher, 2nd person, not inside garage, etc. Or pay an experienced mechanic to check it for you. YouTube has several videos on this topic.

 

Thanks for explaining in more detail - saved me time I don't really have!

 

sorry about the long dragged out process here.

I sprayed carb cleaner around everything that i know of that can cause an air leak- IMT seals, the 6 upper to lower intake joints, both ends of the brake booster vacuum line, both ends of the EGR line, both ends of the accordian tube between the manifold and aircleaner, any sensor openings I saw, the MAF sensor opening, all while watching the rev counter on my OBD2 app, with no change in revs with any of the sprays, other than the 'sanity check' I sprayed directly into the air cleaner opening (that was good for a slight drop in revs.


so.... what would cause an intermittent vacuum leak?


I also tried resetting the computer by touching the positive terminal to the ground... that didn't work... is there another way to reset the computer?

 

Leak below the manifold?

 

Tumbleweed: With the engine warmed up to normal operating temperature, the transmission in park, and your ELM327 scanner plugged in, what is the long term fuel trim at idle and also while you press the gas pedal to hold the RPM steady at ~2,500 for ~30 seconds?

 

On mine when it was running bad when cold it was the COOLANT TEMP SENSOR cheap and easy to replace.Surprised no one mentioned this. Also crankshaft sensor will make it
run bad cheap and easy to fix!!!