Rough idle... Only in drive

[nicholas]

Hey everyone.
Looking for some input.
We have a 2010 Santa Fe. 3.5 v6.
With 80 000 miles.

It drives fine but has started ideling rough only in drive. The plugs have only 40 000 miles on the. Deno iridums.

I just did an induction cleaning with CRC.
Still there.... Only in drive though.
Any ideas?

Thanks

 

[Kage860]

Only in drive? Not familiar with that particular model but that could be engine/transmission mounts.

 

[JLTD]

Plugs been in 40k....so with 80k on the vehicle, the first set was replaced at....40k.

Unless Hyundai was still using plug wires in that MY, I'd say plugs.

 

[eljefino]

Originally Posted by Kage860
Only in drive? Not familiar with that particular model but that could be engine/transmission mounts.


x2

if it's soft in reverse there's the same load of the torque converter on the motor but the mounts are being tweaked in the other direction.

 

[Rand]

in drive there is more load, so lower idle usually.

Define rough? when did this start?

Have you tried disconnecting the battery for 10min?

it would then relearn idle etc.

 

[ammolab]

Is there a throttle position motor or air bleed solenoid that is tasked with increasing the fuel to compensate for the drag of the torque converter. RPM should be same same: Neutral, Drive, AC on or off.

 

[vw7674]

Originally Posted by ammolab
Is there a throttle position motor or air bleed solenoid that is tasked with increasing the fuel to compensate for the drag of the torque converter. RPM should be same same: Neutral, Drive, AC on or off.



back to mount(s) x3.

 

[PPWarrior]

transmission is worn

 

[BrianF]

Different vehicle but similar issues. Trailblazers are known for similar issues. The PCV system gunks up the throttle body, which causes rough idle that seems to be amplified when the transmission is in gear. You have to remove the throttle body and clean front, back and any vestibules. Cleaning in situ does not always work. Unplug your battery for 30 minutes for it to do a relearn.

just food for thought as it is usually a cheap and easy fix.

 

[nicholas]

Its actually fine in reverse.......

Thanks for the input everyone.

I check all the mounts yesterday none are cracked or leaking.

Very strange.

 

[nicholas]

I just had the intake mani off last week. The TB and manifold were very clean. I just gave them a wipe down.

My next step is checking the PCV.
I replaced it last year. The OEM was completly gummed up and not moving at all.

 

[nicholas]

Thanks everyone.

Much appreciated.

 

[tmorris1]

Originally Posted by ammolab
Is there a throttle position motor or air bleed solenoid that is tasked with increasing the fuel to compensate for the drag of the torque converter. RPM should be same same: Neutral, Drive, AC on or off.



RPM should be the same, but the load will increase on the engine while in gear. My suggestion would be to change the plugs as others have said, although 40k seems like low mileage for plugs. I don't know that engine though.

 

[mk378]

Originally Posted by nicholas
Its actually fine in reverse.......

As others said, that's an important clue that the engine actually works OK, since the load on the engine is exactly the same holding the car still with the brakes while in reverse or in drive. What is different is that it is torquing the mounts the opposite direction.

 

[nicholas]

Do you think its the engine mounts or trans mounts.

I think I need to take another look.

 

[mk378]

Stand beside the car with the hood open and watch and listen as someone shifts it from drive to reverse (while holding the brake on the whole time).

 

[eljefino]

Originally Posted by nicholas
Do you think its the engine mounts or trans mounts.

I think I need to take another look.


Engine. You want to do as many at a time as you can afford, ideally all of them, as a strong one will transfer its load to wreck the weak one.

I looked your motor up on google images; there's a fancy looking one on the passenger side, but I can't see the others. Fancy looking ones are, IMO, more likely to go bad.

With it running you should be able to put your hand on the metal halves of the mount to see if it's causing a "sound short".

 

[SteveSRT8]

As an aside, when I broke motor mounts drag racing it was highly recommended to change both the engine mounts AND the trans mount as well.

 

[nicholas]

Thanks

 

[nicholas]

The OEM right mount is $380 CAD - - - and a rock auto is between $60 and $90.

Such robbery for a standard liquid filled mount..................
There is only 140,000kms on the car.

POS.......