Throttle Body causing poor idle and throttle lag?

[toddjb122]

Posting this as an FYI...LR is doing the work now so I'm likely past the point of asking for advice, but opinions are welcome.

Brought my truck in for 97.5K service (at 98.4K miles) and noted two items I hoped to get fixed before my extended warranty runs out;

• Oscillating Idle – truck has had an unsteady idle that will regularly raise and lower RPMs. It has gotten worse over time. Drives fine, but you'll hear it on idle.
  
• The reoccurring throttle lag that has been discussed here before by myself and others...The truck has had an unsafe throttle delay when accelerating after coming to a rolling stop. This is particularly dangerous when entering traffic as there will be a 1 to 2 second delay before the vehicle responds to driver input (stepping on the gas). Past fixes to clear learned driving parameters have only lasted a few weeks.

They said that both problems are related to a faulty throttle body. They don't have error codes but something has led the tech to this conclusion. My warranty company won't cover the part so $280 for the part and $300 for the labor will take care of it for me.

I'm optimistic that this will solve the idle problem. I hope it solves the throttle lag, but I think this is unlikely. Since that problem goes away with a learned driving parameter reflash it seems software related to me. My dealer just hasn't been able to isolate that one or has given up and assumed it is a bug I have to live with.

The 2nd reason for this post was to share this picture. I wasn't exactly sure what a throttle body assembly looked like so I Googled it and came up with this...

The name of the image was "invisible throttle body" and I would agree that it is very difficult to find in that photo.

-t

 

[Disco Mike]

What has been your tune up history, induction cleaning, proper octane levels as well as t/body cleans and idle solenoid cleaning?
I think you haven't found your problem yet.

 

[toddjb122]

What has been your tune up history, including wires, induction cleaning, proper octane levels as well as t/body cleans and idle solenoid cleaning?
I think you haven't found your problem yet.

I perform all the LR recommended maintenance and have also had the throttle body cleaned.

I pointed out to LR that this idle problem materialized immediately following their $75K spark plug change. ? I mentioned it, but they ended up at the throttle body.

The gas is always Premium/Super (not low or mid grade)

 

[Disco Mike]

Have the idle control solenoid cleaned then do an induction cleaning, I think you will be pleased with the out-come.

 

[thorgal]

If it is throttle body they diagnosed,and dealer 's usually right on this one ,you would have to change the whole unit as it is SENSOR inside that goes bad, not throttle flap being stack or not fully closing or opening.Cleaning a body does not really help if you have a faulty sensor .
I also had a fluctuating idle and stalling when sharp turning or stopped at traffic.Have my codes read and it showed codes for MAF sensor, but those codes are actually relevant to THROTTLE BODY itself.If you don,t have a device, that can reset transmission adoptions ( it is a necessary procedure , when changing T.B.), like Faultmate msv2, I am afraid it is a dealer install only option for you .I am a fortunate owner of such device, so I have changed a throttle body myself and performed tranny adoptions reset .No problem since...Another few hundred dollars saved with a little help of MSV2.

 

[blackforestham]

Todd - thanks for the invisible TB picture. Nice. There is a TSB for the "lag" when coming from a rolling (Hollywood/California) stop. It's a Transmission code patch that addresses the issue. Has the Tech considered the fuel injectors at all? Cracked, dirty or split o-rings?

 

[davidfkon]

BFH,
do you have the TSB number?

 

[blackforestham]

I do - somewhere??? It's on one of 3 computers. Start here and it may be easier to hit up your local Service Adviser with questions.

http://www.tsbdata.com/tsb-land-rover.html

 

[davidfkon]

thanks much!

 

[toddjb122]

Todd - thanks for the invisible TB picture. Nice. There is a TSB for the "lag" when coming from a rolling (Hollywood/California) stop. It's a Transmission code patch that addresses the issue. Has the Tech considered the fuel injectors at all? Cracked, dirty or split o-rings?

Thanks. I'll try that if this problem returns before my warranty is up! (we're getting close...)

In the past my SA never acknowledged a TSB for this issue even though I frequently requested it. He was a good guy to work with otherwise but has been let go by the dealership and now I'm working with a new SA who has zero LR experience. We'll see how I do if I have to return.


They did indicate something faulty in the throttle body cap which required the replacement. However, the TB did not issue an error code which is why they could not cover it under warranty. That's odd, but somehow it is what they diagnosed and said they have seen it before.

I'll see how it goes... I did notice that as soon as I left the dealer I still had an unsteady idle when parked at a light with the A/C on. Is that normal? (high idle, low idle, high idle, low idle, etc....) I don't see the RPM gauge move, but can hear it in the engine. Maybe it is the compressor shutting on and off or something but it does sound like it is on full time once I switch on the A/C...