Got a problem with my tintop.

When at idle its rock solid, when running its great but ...

come off the power and the revs drop really low. Say to 500, then jump up to about a 1000, then down to 550, then up and down and then they'll settle and alls fine.

Its slowly getting worse and a couple of times the car has stalled.

any suggestions of what i look at first? Was thinking of checking the hoses are clear for vacum etc (but thinking its more likley to be something electrical)

what engine is it? ive seen something like this on a mates car, fault idle control valve, when coming to a junction it would stall unless you blipped the throttle, it would then sort itself out again, change the idle control motor and it was fine.

If it's injected, the MAF could be on its way out. Alfas suffer from this (amongst other things )

almost certainly the idle control valve mike.

They get gunged up and stick. When you come off the throttle running up to a junction it should open a tad to keep the idle nice when the revs drop, but it sticks, the revs drop a lot, then finally it unsticks and opens too far etc.

Take the idle valve off and wash it out with solvent.

its a vauxhall astra with a XE18CE (or something - basically the 1.8 engine they fitted frmo 1998 - 2001 ish)

Check the Throttle butterfly and surrounding area is not covered in crap before you start chucking ISCV's at it.
Steve.

Not familiar with your engine but had a DOHC Sierra with V. similar problem. Turned out to be faulty MAP sensor and fuel pressure regualtor on its way out.

Hi definatly the idle valve it's probably the same item as on the astra and corsa and i am always having to sort them on family members cars.

cheers matt

Can also vouch for the ICV. Take it off give it a good clean with carb cleaner and bolt back on. Often they will need resetting though, usually by turning the ignition on, a few pumps of the accelerator then turning car over.

You may be able to avoid this by leaving the ICV connected while you clean it. Not sure if this has any implications though so your best bet is to find out how to reset the ICV if you need to at all.

[Edited on 2/2/2007 by greggors84]

when the ICV is off unbolt the solenoid from the body and clean that thourougly maje sure its free to move. also make sure none of the vaccume pipes to the tb are bunged as this leads to too much crankcase gases blocking up the ICV

i did all of this to my cav X20XEV and its been perfect ever since

turns out your all right apart from one detail i forgot to tell you.

XA1.8XE1 engine as fitted to my car is the only one that has the ICV integrated into the throttle body. Every other one has it detachable.

Going to have a play at the w/e and see about changing some sensors (some people have had success changing the air temp sensor - although i can't see it working for me). If not its new throttle body time and getting a vaux dealer to program the ecu to it.

bloody car never has cheap faults!