Revs hunt when idle

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mikedaws
Apprentice Bongonaut
Posts: 4
Joined: Sun Jul 24, 2016 7:39 pm

Revs hunt when idle

Post by mikedaws » Sat Sep 12, 2020 7:27 pm

I have started having a problem with my Bongo 2001 automatic petrol.

Sometimes when I am stopped at a temporary traffic light or waiting to pull out from a petrol station. That is in drive(automatic), foot on brake, the revs suddenly dip the go back to where they were at least twice in a row. I think they say the revs are hunting.

I also get this when I am turning on a roundabout or/and just accelerating off the roundabout. I am not sure if it is hunting but foot hard down seems to sort it out eventually. It feels like fuel problem or a sensor messing up the engine mapping.

Someone suggested a faulty MAF sensor. Seems to only happen from low revs. Okay when above 30mph.

Any ideas?
Bongolia
Supreme Being
Posts: 1511
Joined: Fri Apr 01, 2016 2:17 am
Location: Folkestone

Re: Revs hunt when idle

Post by Bongolia » Fri Sep 18, 2020 9:34 pm

You should check the basics first before suspecting sensors etc they can be an expensive learning curve.

First I would go for a check of all the air and vacuum pipework look for cracks etc.
Air leaks wil cause the idle speed control valve to try and compensate and your emmisions will be all over the shop too.
If they are OK then check the idle speed control valve and give it a clean out ( have a search on here ) not a bad idea to give the ISCV a clean out any way.
Good luck.