Help needed with the idle problem

[derpomz]

Ok here we go again.

When the car is idling in park or neutral, it purrs like a kitten, no problems.

When i have to slow down or stop at lights or an intersection and i am in drive, it jumps and twitches like its about to stall. There are no acceleration problems in fact its very quick of the mark. I just cant figure out whats causing this and why.

Has anbody any idea what may be causing this. I have changed to high octaine fule to try that, but it doesnt seem to stop it.

Also

Can somebody tell me what the Plenum filter does. I have noticed there is very little left of the foam and have oredered a new one.

[Hoges]

Ok here we go again.

When the car is idling in park or neutral, it purrs like a kitten, no problems.

When i have to slow down or stop at lights or an intersection and i am in drive, it jumps and twitches like its about to stall. There are no acceleration problems in fact its very quick of the mark. I just cant figure out whats causing this and why.

Has anbody any idea what may be causing this. I have changed to high octaine fule to try that, but it doesnt seem to stop it.

Also

Can somebody tell me what the Plenum filter does. I have noticed there is very little left of the foam and have oredered a new one.

Could be that the torque converter lockup is not readily disengaging and it's stalling... like slowing down in a car with manual transmission and not pressing the clutch pedal soon enough. To test this theory...try shifting it into neutral as you slow down and see if the rough running is lessened...

The plenum filter is to stop rubbish being sucked into the fresh air intake of the heating system before it gets to the pollen filters.

PS you're really getting in to this and asking the right questions!! good for you!!

[derpomz]

Could be that the torque converter lockup is not readily disengaging and it's stalling... like slowing down in a car with manual transmission and not pressing the clutch pedal soon enough. To test this theory...try shifting it into neutral as you slow down and see if the rough running is lessened...

The plenum filter is to stop rubbish being sucked into the fresh air intake of the heating system before it gets to the pollen filters.

PS you're really getting in to this and asking the right questions!! good for you!!

Yes its like a drug. Dont know if i should keep it, she wants me to get rid, or go nuts and really do it up.

Ok another dumb question, whats the torque converter and where is it also how do you fix it.

After many hours of reading the RAVE disc i bought, i can see how its helpful in taking stuff apart etc, but i am disapointed it doesnt cover problems and how to fix them. I suppose with these cars there are too many to mention.

[PhilipA]

Ah there are possibly 2 mundane explanations.

1 when the injection considers that you are overriding IE TPS closed, speed sensor pulsing , revs over 1500RPM, then the injectors will be turned off.

When you drop below 1500RPM the injectors are switched back on. This can give a slight surge while pulling up.

2 the transmission changes down to 1st as you stop to enable a speedy getaway . Sometimes the change to 1st can be rough particularly if you have slop in the driveline.
The less mundane are maybe the post above.

Maybe the IAC ( inlet air control ) valve is lazy and letting the engine revs drop before recovery. The Thor has a very robust valve but the GEMS has a similar valve to the earlier RRC 14CUX.

On balance I would be looking at the IAC valve AKA stepper motor if the car is a GEMS ie pre 1999.

Regards Philip A

[derpomz]

Ah there are possibly 2 mundane explanations.

1 when the injection considers that you are overriding IE TPS closed, speed sensor pulsing , revs over 1500RPM, then the injectors will be turned off.

When you drop below 1500RPM the injectors are switched back on. This can give a slight surge while pulling up.

2 the transmission changes down to 1st as you stop to enable a speedy getaway . Sometimes the change to 1st can be rough particularly if you have slop in the driveline.
The less mundane are maybe the post above.

Maybe the IAC ( inlet air control ) valve is lazy and letting the engine revs drop before recovery. The Thor has a very robust valve but the GEMS has a similar valve to the earlier RRC 14CUX.

On balance I would be looking at the IAC valve AKA stepper motor if the car is a GEMS ie pre 1999.

Regards Philip A

Ok thanks. Does this have anything to do with the MAF thingy bob. Should i take of that big block thing that has 4.6 on it and clean the bejezuz out of it. I have no problem with hill climbing or any other running matters for that. Im wondering if its just pure muck in the air intake, but what do i know im just having a stab with my little bit of knowledge.

[PhilipA]

I am not sure on a GEMS, but I think I have seen a photo where it is placed at the front of the inlet manifold.It cannot hurt to clean around the throttle blade either.
The IAC is a cylinder shaped thing about 40MM long with a plug with 4 or 5 wires going to it.
There are some pictures here
https://www.google.com.au/?gws_rd=ssl#q=range+rover+p38+stepper+motor
Regards Philip A