Hi everyone,

First post so I hope I’m following order and doing it in the correct bit.

I’m chasing down a slightly lumpy/rough idle on my 2006 Discovery 3 4.4. It doesn’t sound like a stumble or miss but the shake/vibration is felt through the car every so often. It’s not consistent and is felt at idle. Visually like this ___—________—__—_____-. I a consistent vibration through the car at around 1k rpm but this is consistent and feels inline with the engine rpm and is mot a random vibration.

Note that this vibration is felt in neutral, park, drive when stationery. When in drive the vibration feels reduced and it also seems to be more prominent when cold. I have zero vibration or roughness when driving the car is buttery smooth.

Steps I have currently taken: Cleaned MAF, cleaned throttle body, cleaned EGR, replaced air filter, reset engine adaptations

I have JLR SDD and here’s some data I have collected from the car:

MAF 6g/s

No misfires on misfire counter

No fault codes

RPM stable and not fluctuating more than 10-20rpm

Intake cam timing bank 1: 41.532*

Intake cam timing bank 2: 45.778*

Car is running in closed loop

Long term fuel trim: B1=1.56% B2=0%(B2 seems to not change on graph?)

Short term fuel trim: B1=-3.13% B2=-4.69%

PCV is shown to be operating, but unsure if it’s doing what it’s supposed to do

Can anyone spot anything wrong with the above data read? Or does anyone have any suggestions?

I’m trying to do as much diagnostic as possible rather than throwing money at it till something sorts it. Can provide any more data at request I’m just not sure how to interpret the rest

I’m leaning on it at this point being engine mounts to be honest, engine itself seems to be running quite happily.

HACKCHILD said:

Hi everyone,

First post so I hope I’m following order and doing it in the correct bit.

I’m chasing down a slightly lumpy/rough idle on my 2006 Discovery 3 4.4. It doesn’t sound like a stumble or miss but the shake/vibration is felt through the car every so often. It’s not consistent and is felt at idle. Visually like this ___—________—__—_____-. I a consistent vibration through the car at around 1k rpm but this is consistent and feels inline with the engine rpm and is mot a random vibration.

Note that this vibration is felt in neutral, park, drive when stationery. When in drive the vibration feels reduced and it also seems to be more prominent when cold. I have zero vibration or roughness when driving the car is buttery smooth.

Steps I have currently taken: Cleaned MAF, cleaned throttle body, cleaned EGR, replaced air filter, reset engine adaptations

I have JLR SDD and here’s some data I have collected from the car:

MAF 6g/s

No misfires on misfire counter

No fault codes

RPM stable and not fluctuating more than 10-20rpm

Intake cam timing bank 1: 41.532*

Intake cam timing bank 2: 45.778*

Car is running in closed loop

Long term fuel trim: B1=1.56% B2=0%(B2 seems to not change on graph?)

Short term fuel trim: B1=-3.13% B2=-4.69%

PCV is shown to be operating, but unsure if it’s doing what it’s supposed to do

Can anyone spot anything wrong with the above data read? Or does anyone have any suggestions?

I’m trying to do as much diagnostic as possible rather than throwing money at it till something sorts it. Can provide any more data at request I’m just not sure how to interpret the rest

I’m leaning on it at this point being engine mounts to be honest, engine itself seems to be running quite happily.

Click to expand...

Has it always had a lumpy idle in your ownership.
Wondering if the previous owner fitted uprated high lift cams.
My rover V8 is lumpy at idle die to the cam.

Montyjohn said:

Has it always had a lumpy idle in your ownership.
Wondering if the previous owner fitted uprated high lift cams.
My rover V8 is lumpy at idle die to the cam.

Click to expand...

This one’s an AJ 4.4 V8 so I’m not entirely sure if that’s as common as on the rover. I’m yet to completely cure it but getting engine mounts done soon to see if that helps. I’d imagine they are rather shot anyway.