Engine RPM will not go below 1100rpm in Drive

[V8 MAN NZ]

Please help. driving me nuts. Wellington NZ based
2012 VE series 2 L77 SSV Auto
130k km
OTR installed, with cat back exhaust and tune approx 7 years ago.

3 weeks ago out of the blue, the car developed the following issue.. When in Drive, the engine rpm always tries to stay at 1100rpm when I take my foot off the go pedal (as in it will not go lower by itself). In neutral or park it sits at 600rpm (normal). At the lights etc when coming to a stop, it will stay at 1100 rpm for a few seconds and then drop to 600. This means that around town I am constantly having to use the brakes to slow the car.
Since this has been happening, under advice, I have cleaned the throttle body and reoiled the OTR air filter, Reseated the sensor do-hickies around the air intake , checked for any fault codes using ODB 2 reader (there were none) and looked for any vacuum leaks. Nothing has worked.

Does anyone have any other ideas on what could be causing this or have seen it before.

 

[07GTS]

if u have reoiled the otr if u are using a maf u may need to clean it as the oil can get on the maf sensor and cause issues, may not be problem but worth a check

 

[V8 MAN NZ]

if u have reoiled the otr if u are using a maf u may need to clean it as the oil can get on the maf sensor and cause issues, may not be problem but worth a check

thanks for the reply. Always careful to not overoil the filter. not been an issue before over the last 7 years since the OTR went in.

 

[vr304]

Try cleaning the maf, they get dirty over time regardless of how careful you are oiling your air filter, you need maf specific cleaner for it can buy it at the likes of super cheap auto and repco etc

 

[vr304]

They are also known to have throttle body issues so you may need a replacement but try the basics 1st

 

[V8 MAN NZ]

thanks for the

Try cleaning the maf, they get dirty over time regardless of how careful you are oiling your air filter, you need maf specific cleaner for it can buy it at the likes of super cheap auto and repco etc

Thanks for the reply. MAF was cleaned with proper MAF cleaner and ditto for the throttle body.

 

[V8 MAN NZ]

So I am just back from the mechanic shop and they could not find the cause either. Ran all the usual tests for vacuum leaks, opened up the throttle body to check the gears, gave it all a reclean etc. Could not get any codes to show. they were able to confirm the throttle percentage is sticking at 14% throttle when driving and no accelerator pressure and it should be much lower. that would explain the symptom I get with having to ride the brakes in city traffic. Next step is to try the local Holden Servicing Centre and see if they have better luck. booked in for just over a weeks time.

 

[ephect]

I wonder if the ecu is trying to compensate for something that's not there. IE engine load etc.

Be interesting to see if it's ecu attempting to hold the throttle at 14% or the throttlebody has some wear causing your issue.

Does any mates have the same car you can test swapping throttlebodys to see if the symptoms follow or stay.

 

[vr304]

I tend to agree with ephect, if it’s possible to borrow a known good throttle body then put that on and see if the issue goes away

 

[Asmodai78]

I had a very similar problem where once everything was warmed up the revs wouldnt go below 1000 rpm when slowing down, it ended up being the torque converter, I cant remember the exact problem but it fixed the issue.