Engine cutting out when revs dropped, idles fine.

[veevee]

Any ideas?

My revs tend to dip very low if I come off the throttle quickly. About half of the time low enough to cut out. This is incredibly annoying as it sometimes happens coming in to traffic lights, and often whilst doing a 3 point turn!

Have noticed my power steering goes sometimes too while the revs are dropping, not much fun.

First stop will be a new battery I think, but fairly clueless other than that!

[ian_uk1975]

Could be a vacuum leak. Power steering going when the revs drop is because the power steering pump is no longer being driven fast enough to operate efficiently, hence the increase in steering effort.

Check all the under bonnet hoses. Vacuum hoses are usually small bore hoses... one may have become detached from a port somewhere.

Other than a vacuum leak, it could be an erratic/sticking idle speed control valve. These can often be fixed by cleaning them out.

[veevee]

Forgot to mention, it idles perfectly once running. Its only if the revs are dropped quickly (including at atartup) this happens.

[maniac0796]

You'll have to be more specific, as in, what car?

Clean out your throttlebody

[scarble]

maniac0796 said:

You'll have to be more specific, as in, what car?
Clean out your throttlebody

Or more specifically your idle air valve and like he says, what car?

[Krikkit]

scarble said:

maniac0796 said:

You'll have to be more specific, as in, what car?
Clean out your throttlebody

Or more specifically your idle air valve and like he says, what car?

Yep - sticky idle air valve sounds like the cause. Had this last week, a quick blast with some carb cleaner and it's perked right up again.

[scarble]

Krikkit said:

Yep - sticky idle air valve sounds like the cause. Had this last week, a quick blast with some carb cleaner and it's perked right up again.

but remember to let the cleaner evaporate fully, like, really fully.