Astra Mk4 idling ploblem

[stavroshamster]

I have a 2001 Astra which I have owned for about a year, after inheriting it from my brother.

Basically the problem is that when idling at e.g. traffic lights, the revs sometimes drop rapidly as if the car is about to stall (although it hasn't stalled yet), then bounce back up again. It will do this about once every 2-3 seconds for a few times, then there might be a gap, then it might do it again.

It doesn't do it all the time though, and there is no clear pattern to it I think (i.e. it does it sometimes from cold, and other times when it's been running a while).

When it does it the lights also seem to flicker, and there seems to always be a slight flicker in the dashboard lights. The dashboard lights also dim if you put the rear window heater on, and the revs drop slightly, but don't bounce down then up which is what happens when it feels like its about to stall.

I have read something somewhere else about carbon deposits on the throttle body causing a similar problem, but have inspected it and it looks pretty clean.

Any thoughts? Do you think its something electrical?

 

[bongos]

The dashboard lights also dim if you put the rear window heater on, and the revs drop slightly, but don't bounce down then up which is what happens when it feels like its about to stall.

Not sure about your other questions but I think this is fairly normal. The rear window heater puts a large drain on the battery so revs may drop slightly. I don't recall it being so common in newer cars but it used to do this on my old Nova!

 

[Jimbo1978]

sounds like you have one of two things. An air leak or a dodgy idle air valve/throttle body. What engine is in the car i.e X18XE1 or Z16XE. The throttle body may just need cleaned out. Some idle air valves can be changed on the side of the throttle body. As for the air leak this can be checked with a can of carb or brake cleaner.

Jim