Erractic Idling

Sounds as though it may be the idle by pass valve, this allows for engine load change at rest, i.e. air con kicking in or putting on the heated rear screen for example.

I may just need a clean out that said it could also be an air leak on the induction side somewhere too.

It is a common fault and whilst everyone says it is different things, the most common reason is a faulty ECU. If you have the A/C on, switching this off will help it too. Mine did it when new (1998) but hasn't done it for the past 2 years.

Just a quirk from a sometimes quirky car..........

Hi,

Thanks for the reply.

I hardly use a/c. The ecu had no fault codes when last booked for this problem, they could not find a fault. Also the ecu had been changed when the service light would not go out, but this did not fix that particular fault, so they changed it back for the original ecu.

The problem can be intermittent, and never seems to happen when the dealer has it. However with enough city driving it will show itself.

Thanks

"Magnumforce" wrote

I will preface this by saying I don't know anything about cars, but our 99 V70 had an erratic, rough idle, almost to the point of stalling at stand-still. We took it in for repair, the throttle body was cleaned, and a cracked serpentine belt replaced. Problem solved!!

The car is now running pretty good with an exception, a loud, sporadic cracking noise....It sounds like ice is hitting the windshield!! This is happening about twice a day now whether I'm turning, standing still, backing up etc... Any ideas?

Thanks!!

"Tumkin" wrote in message news: snipped-for-privacy@posting.google.com...

I get a sporadic cracking noise from the dash on my '91 740. It is caused by having the heater on high. It's the plastics expanding when they get heated up when it's cold outside. My older 740 and 240 don't do this, but I have noticed that on the older cars the plastics are thicker with more sound deadening material on them. IE. the inner covers on the doors on my '86 are twice as thick as the ones on my '91, and the roof headlining is also twice as thick. Aslo the '86 is a quieter drive than the '91. I guess what I am saying is that the build quality of the older bricks is better. The later ones in my limited experience have more "accountant" led design than the older ones which have more "engineer" led design. This is only on the plastics interior side. I think that the outer body shell is still just as good if not better on the newer cars. My ideal would be to find a perfect interior from say an '86 and build it into a '94 shell. My '91 also tells me when I'm doing over 85 mph by a noise from the top of the wind screen that sounds like someone trying to start up a set of bagpipes. It has to be the black strip covering the top A pillar where the windscreen meets the metal. No leaks are apparent, but one of these days I'm going to superglue the damn thing down. At rest I can't see the problem, so I'm going to have to overclock the wifes hairdryer and point it at the screen to see where the noise is coming from. Stuart.

Thanks Stuart. Another poster from back in April wrote about the same noise and attributed it to the plastic too...He said the plastic on his car was actually cracking where it met the windshield. Our car is the same year, but I don't notice any cracks.

No actual cracks on mine either on my '91. My older '85 started to crack across the top of the instrument panel, but the plastics used felt different. The newer car seems to have thinner plastic, or the older one had more sound deadening material stuck to the plastic. Either way, the older car never crackled but did crack, and the newer car plastic looks better but crackles, but only when the car is being heated up from very cold. If you see what I mean.

Stuart