Hello Team,

Looking for some ideas as to potential cause of an issue on my 2005 Super V8 with 117K Miles. Prior maintenance history is generally unknown as i purchased the car with 100K miles and been slowly getting it operational.

Primary issue is that there is pronounced engine vibration in neutral at 1200 RPM. Engine is smooth prior to reaching 1200 RPM and goes back to being smooth around 1400RPM.

Not sure if this related, yesterday on the freeway the vibration got worse and I saw the check engine light blink. plugging in an OBD tool and using Torque Pro, got following codes:

P0301 - Cylinder 1 misfire
P1111
P1313

I went ahead and swapped the coils between cylinder 1 and 3 to see if it is the coil, plug or something else. Cleared the codes and waiting for additional codes to return so far nothing. However, the 1400 RPM vibration persist.

I have seen quite a bit of mention of LFT numbers. Not sure if they are of value, i am attaching Torque screenshots for reference, have no idea how to interpret them.

An unusual issue I saw is that Torque Pro throws some high (11K-16K) odd RPM values intermittently when I rev to 1200-1500 RPM. Almost as if the OBD is getting bad data when the engine is vibrating.

Generally, car has no issues starting or any hesitation when driving, shifts are smooth. There is some body vibration when driving at high speeds, but I believe that is either due to worn out rear upper and lower control arms or driveshaft problems, have not gotten to sorting that out yet. Cats were replaced as an aftermarket parts due to California requirements.

Thank you in advance.




Frank

 

I don't think that there is much wrong with the fuel trims

You swapped a coil but not a plug when a dodgy plug is the first possible cause of P0301

Code P0301 Jaguar Possible Causes
Faulty spark plug
Clogged or faulty fuel injector
Faulty ignition coil
Fuel injector harness is open or shorted
Fuel injector circuit poor electrical connection
Ignition coil harness is open or shorted
Ignition coil circuit poor electrical connection
Insufficient cylinder compression
Incorrect fuel pressure
Intake air leak

Read more: https://www.autocodes.com/p0301_jaguar.html

 

Thank you for the feedback. If the cylinder 1 misfire reappears all 8 plugs will be replaced with coils for sure.

I added a fuel cleaner and filled up tank over the weekend and been driving around. No codes yet, however the engine vibration at 1200 rpm in netural remains present and consistently reproducable.

Regards,
Frank

 

When you feel the vibration does your OBD tachometer reading bounce around more? Does it stay at a high RPM? You should have a coolant reading - possible bus issue.

 

Flashing MIL = misfires so bad they're causing catalyst damage - be worried

P0301 is typically a bad/contaminated coil (or wiring).

 

After fixing the misfires if you still have the vibrations the engine and transmission mounts might be the culprit?
Your at the right miles for those to be worn out too.
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Thank you for the helpful information. Keep trying to pull fresh fault codes but even after 2 weeks of driving (although gentle) still have P1000 as the only code showing up after the coil swap, hoping it clears up soon and starts to log faults. The vibrations are still there.

Transmission mount was replaced about a year and half ago, the engine mounts are questionable, but the engine does not appear to lift when I put it in reverse and forward with engine revving.

Not sure if related, there is a small coolant leak from the front of the engine, hard to tell where it is coming from, would need to remove stuff to track it down, suspect water pump gasket. Also getting some bad body vibrations on high speeds but I think those are related to worn controls arms in the rear. Front upper/lower were replaced couple of years ago.

Frank

 

It's most likely the water pump itself and not the gasket. Also have the 2 front plastic cooling pipes been changed?
I can't remember if you have done any work in that area yet?
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I replaced the water pump couple of years ago, did not plan it properly as the original bolts were stripped and had to put them in as is. As a result the water pump was a bit loose and weeping. Ordered new jaguar bolts and went back in few months later and torqued them to specs but I think by then the loose bolts likely caused movements that damaged the gasket. Just a theory till I get back in there and see what is leaking.

The coolant reservoir was also replaced as it had leaks. Sorry I am not aware of the plastic pipes as everything else coolant related appears to be rubber pipes.