High revs on startup then lumpy idle

So the brothers X308 has a very high startup >2000rpm then drops to a very lumpy idle, it also has a funny noise from the torque convertor.
Would the high start up possibly be due to the TQ draining overnight causing less resistance?
With the lumpy idle it smells rich could either a pin hole in the pressure regulator or a leaking injector be the cause?

I think i’d start by checking the hoses around the intake for an air leak and give the throttle body and maf sensor a good clean. The throttle butterfly often sticks due to build up around it. The butterfly may also need reseating by backing of the screws attaching it to the spindle and retightening.

Sorry should have said he has already performed a smoke test and there was one small pin hole just where the full load breather connects. I have supplied a replacement inlet trunk so that will cure that, currently its taped up with electrical tape. We are suspecting the transmission may be a bit low on fluid as there is a slight whine so its being booked in to have the level checked.

I don’t think these are related, the ECU will want to set the idle to min/max rpm, like 600/1200 as set limits. Did you read out the obd?

Does sound like a malfunction and the ECU trying to keep it running by adding fuel; if it’s a v8 it might overfuel the bank that works correctly in the process. Any faults in that direction?

But do check the transmission before it’s ruined, potentially.

Thanks David, the car is booked in for a check of the transmission on 8th Dec. It is the 3.2 V8 once the revs drop from the initial high idle then the exhaust smells really rich. I think he has changed out the temp sensor but need to check, currently on the ferry back to the North Island.
My basic OBD11 scanner didn’t bring anything up :confused:

I saw a similar post recently. Was it you ?

These engine do this if the battery or ecu has been disconnected.
Try yourself disconnecting the battery and see if the symptom is the same or not so bad.

If its the same, it could be the engine ecu no longer has a +12v supply for its memory

Hi Andy, its been doing it for a while so the ECU would have learned the startup by now. Its my brothers car and it is 900+ klms away, so doing things by remote.

To me it could be forgetting what it’s learnt as it doesn’t have power.

Not that a reset would help.
It was just s suggestion