105k miles, 8k OCI w/ German Castrol 0w40, 8k on air filter, recently cleaned TB but will check this evening, no CEL, zero visible leaks or anything else.


I mentioned this a while ago but it's getting worse, and mentally I can't accept that it's just a "cold engine thing" anymore with these cars. It's a freakin' Jag engine, I know it shouldn't be doing this.

I'm not really surprised that the motor would be hesitant to rev when cold (say running for 5 min and 24 degrees out or so). But yesterday at idle the vehicle developed a slight "shake" actually. I revved it up a bit and as it climbed through 1500 there was a noticeable engine vibration. Also when I let it drop back to idle it almost falls on its' face down to just under 500rpm for a second.

Granted there's not much I can do if it's actually mechanical (though I'm not sure what would cause it) as I'm not going to dive in and do a tear-down.

BUT I suppose there's still some possibility that it's actually a slight misfire instead?

Would any live data be able to clue me in as to what cylinder is causing it? I think there was a "roughness" data feed for each cylidner, if so I could always move a coil around or something. It could also be induction related to valves and lifters when cold I suppose. It's really not something I'd point out or be concerned about when it's warm, so that's a decent hint.

I don't recall the engine acting this way (to this extent) before, and my RRS definitely wasn't.

I've never been much of a "spark plug miracle" guy myself, but I'm starting to think that I might be way overdue.

She's definitely lost a little power as well, although the 32" wheels/tires made most of the impact.

I'm actually kinda worried about towing with her now, which is unfortunate because it's been a DREAM towing rig in the past.

 

Not sure if mine is the same, since it is at 1100 rpm, but I also have a shake. I haven't been able to track it down at all. Mine does it when cold and warmed up. Does it in gear and out so I know it is the engine. Was planning on replacing pulleys and belts and also spark plugs soon to hopefully fix it. Only other thing I can think of is engine mounts. Do they usually go bad and where are they located?

 

still on the original spark plugs?

 

I haven't heard of them going bad, but I suppose there aren't TOO many high mileage LR3/RRS out there yet. I'd expect it to be an issue at all speeds though and especially under load as the torque tends to rotate the engine.

I'll keep you updated as there's about 10 things I'm going to punch out to see if they have any impact, hopefully starting this evening.


DavC: As far as I know they're original - I got the vehicle with 87k ish, I do have the full like 14 page history but don't recall them being done, that would be rather early for a dealership to do it I guess.

I also forgot to mention that there are no codes (it's not THAT severe) but I'm hoping that doesn't rule out a missfire and send me back down the "balance" route.

 

Quick update:

I ordered a few parts and made a list of things to check.

1) Got new plugs... H0LY #@%#$% the things 'aint cheap!
I'm a shop manager at a restoration facility and was lucky to get one of our local parts places down to $9.99 each! I've gotta say that's the most I've ever spent in my life on a set of spark plugs lol. Retail was about $16 but I guess you can get them online for $13. Yikessss.

2) I also got the LR004160 capacitor for the ignition coils, as I'm fairly sure my '06 has the old design. Apparently if the old design fails it can cause interference, but considering the feedback capability of these ignition coils, I'd expect that to throw some kind of CEL as the workshop description says they can throw multiple types of codes for each coil.

3) Going to inspect PCV, might end up soaking it - LR wanted $58 and I can get it for $35 online so I decided to hold off on that.

4) Replace dip stick o-ring, have heard many issues related to this not sealing properly and considering how important it is, there's no harm in throwing a new one on there (I have an entire set).

5) Clean MAF and TB (again)

6) Attempt to tighten the stupid exhaust manifold bolts. I already know they're loose as I can hear the tick under load against walls. RRS did this too - I suppose this has the potential to screw things up. If it's within the correction range of the EFI it'll adapt without throwing a code (so there's potential for A/F ratios to be off).

7) May remove the injectors and soak them in carb cleaner. Many might be surprised how well this works. I haven't looked at how complicated injector removal is yet however, and from what I hear the AJ-V8 injectors rarely clog.

8) Clean/inspect all the coil boots and signal wires. This should be at the top as I'll do it with the plug replacement. I've read about some cars having damaged wires to the coil packs which would obviously screw up all kinds of things. From past experience I also know how messed up the springs and boots and get after 10 years of dirt/dust/moisture and heat cycles. Might sand the electrodes and soak these as well. Hopefully the wire harnesses are all okay as that might ground me (no pun intended ) for a bit while waiting on new ones.

9) This is more performance related and not vibration related, but I'm going to reset my trans adaptation learning, since I forgot to do so after switching up to 32" tires from the stock 30's - ALL shift points and load calculations will be totally different so I really should have done this earlier.

10) BG or seafoam induction and injection service - I've never done one and I've heard of a million stories of these 4.4's throwing CEL's after the service so I'm hesitant. I know these motors get kinda nasty though (TB is always gross) so I'm really tempted.

If I don't, I'll run some good injector cleaner through there at the very least.

I intend to at least do a few of these tonight, starting with the plugs, capacitor, o-ring, tb/maf clean, etc. I'd like to attempt the exhaust manifold bolts but I might be done for the night at that point. Depends how much beer is left. I'll let you all know how she runs afterwards.

 

Funny, mine also has the tick under load. I had the shop take a look to see if they could torque some of the manifold bolts, and they said a few did move slightly, but the noise is still present.

 

Just a word of caution. If the coil packs haven't ever been removed and you're over 100k miles, there's a decent chance they'll be stuck on the plugs pretty well. I ended up tearing one of my boots off when I did my plug change and had to get a new coil pack. Also had to buy a set of picks in order to fish the boot out of the hole. When I had another coil pack fail a few hundred miles ago, I noticed they the boots were already starting to stick pretty well (probably been 15k miles or so). I might give some thought to greasing them or something in the future, though I honestly am not sure whether it's the inside of the boot (against the spark plug insulator) or the outside of the boot (against the engine) that's sticking.

 

Thanks! I wish I could get something in there first like WD-40 but I doubt that'll get up into boot backwards.

Ideally they'd have dielectric grease in there, but it's an LR so who knows..

 

Oh FML.

Just finished the seafoam induction cleaning - let is soak, took it for a "spirited drive"...

Climbed to about 4k and the valvetrain made a racket as it held steady at those revs and wouldn't climb, "reduced engine performance" and CEL illuminated.

Afterwards the engine developed ZERO power past 2500 RPM. Funny thing is that it still has decent low end torque, but if you floor it she'll climb SLOWLY and hang around 4k regardless of throttle position. Almost like the valve timing has totally given up and reverted to a low engine speed setting ONLY.

Not to toot my own horn, but I'm pretty good with all the diagnostics at my shop - especially the more modern computer-related issues, and my number one rule is not to believe in coincidences (ie. the seafoam DID have something to do with it) BUT in this case, I RARELY let the vehicle rev very high or develop a lot of power - average speed on trip computer is probably 20mph. I'm always in traffic. This is also symptomatic of the problems I've noticed with reduced power lately. I do think the seafoam may have contributed, but whatever set this thing loose was already happening - just not enough to trigger CEL/reduced performance.

Going to try to pull the code, but I don't think this cheapo scanner will do it.

EDIT: Was able to read/clear codes - P0175 and P0172; system too rich bank I and system too rich bank II. So to be expected with excessive residual seafoam I suppose (?!) - I cleared the codes and the engine revs freely to redline but it's parked in the shop so I can't put it under any load. I'm hoping "reduced engine performance" simply cuts ignition advance and variable valve timing till you clear the codes.

Off to complete the plugs and capacitor change!

PS I pulled a stored code (I remember now, CEL that happened a while ago and went away) and it was a cylinder 8 misfire, so perhaps there is a slight miss still that's just barely within limits.

 

Plugs just pulled.

Front of image (err bottom I suppose) is front of motor looking towards firewall).

Edit: ok phone rotated it grr. Right side of image is the front grill, left side is firewall