DaveK

For the past week, I've had an occasional idle hunt - only a few hundred rpm, but it's noticeable because the idle is usually perfectly steady. I did clean out the ISV about a week ago (although I didn't have idle problems before that - just felt like it) - but I didn't leave the brake fluid in it for long so plan to do it "properly" this weekend. I wondered if that was the cause of the idle, but this morning I noticed something else.

My car was a bit hesisant a few times - this was at constant speed (about 40mph) but also did it at very low speed (5mph). It seemed like a very brief loss of power - it didn't "jolt" - just suddenly felt a bit dead for a split second then picked up again. Did it a few times in a row, and then for a few minutes when stuck in traffic.

I assume it can't be the ISV since that doesn't do much when I'm driving along?

I can rule out my oxygen sensor (don't have one). Rotor caps are 20K miles / 2 years old.

At the moment, it's not really serious enough to be a problem - more like a warning that something is going wrong. Any ideas?

Youcef

Did you have a look at those head light levellers?

DaveK

I'll take a look - it was fine the last time I checked it, although it does connect next to the ISV so maybe I disturbed it. Would be surprised if that caused the hesitation at 40mph though.

Roygarth

Hi Dave

Mine always idle hunts for 10/20/30 secs depending on how long since last used, but always settles down. Is this OK?

Thanks!

Youcef

Guees that's a point, never know though might pick up somthing along with another check on the ISV. I pulled my ISV about 3 weeks ago and gave it a clean which certainly helped matters. This combined with fixing the leak in the headlight leveller sorted the hunt in my idle.

When is the next plug change due?

DaveK

I'm not actually sure when the plugs were last changed. Is it part of a 12K service? Don't think I've ever seen plugs on the parts list after my services - I think I will make sure they are done next time. But that's not due until August / September time (about 6K miles yet).

DaveK

It seems to have gone. I cleaned the air flow sensor (including taking the top off and cleaning inside), I put some injector cleaner in and I replaced the coils. Did all this at the same time.

Didn't expect any difference - but it hasn't done it since (done about 600 miles since then I think). It was intermittent so might still be there - I've ordered dist. caps / rotor arms today since I know they're a bit pitted anyway. I hope that all this together is enough to cure it.

J Henry

I had a similar problem with my 1990 C4. Intermittent cutting out at certain speeds. Changed rotor caps, coil leads, but no cure. Finally changed the spark plug leads & has been perfect ever since. Hope this helps.

Christer

Dave, did you try the 'bits' from my car that I gave you the other week or did you not need them? If you intend on keeping them, can you send a cheque ASAP?

DaveK

I haven't tried them (yet). But I am interested in keeping them, so I did actually plan to discuss costs with you.

I reckon since they are 14 years old, they are probably worth about 10p.

Thomas Linser

Folks!

What has the head light leveler to do with the Idle!!
Sorry for the stupid question...

Thomas

DaveK

Because it's vacuum (which I can't spell) operated - and it gets the vacuum from a pipe which connects to the intake side. So if there is a leak in the connection, they you basically have a bit of a leak on your intake side.

Christer

Lets say that if you never talk about how good-looking you think you are ever again, then we are quits. I can't laugh so hard very often, I am sure my spleen was trying to get out through my nose half an hour ago.

Thomas Linser

Dave!

Thanks for the info! Do you by any chance have a photograph showing the vacum er..vacuumm...er...vacuum (god Latin must have been such a pain in the a.. language) pipe! I have to look at this pipe since my Idle is not that convincing, although I have LWF with the RS chiping which should cure out my idle prob's!

Thanks in advance

Thomas

DaveK

I haven't got one - but it's easy to find. Look at the intake area in the engine bay - kind of to the right of the ISV. You'll see three pipes joined together - kind of like this :

.....|
.....|
..../.\
../.....\

One of them goes to the leveller switch in the cabin. But the easiest way to check it's not your problem is to see if your headlight leveller works.

The pipe runs from the switch, under the drivers side carpet and back to the engine bay. When mine was damaged, it was actually crushed under the driver carpet. Didn't cause me an idle problem, but also didn't let the vacuum through.