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Very Intermitent Eratic Idle - no pattern

840 views 8 replies 3 participants last post by  alfapash 
G
#1 ·
Guys

I have searched and read various thread that mention eratic idle issues.

The issue I have is that I do have eratic idle issues sometimes, but there is no pattern as to when it will happen.....so not sure where to start. The issue is common I guess i.e. when it happens (slowing down) the revs drop to virtually cutting out, then rise to about 1000 - it does this a few times before becoming steady.

But, it does not do this all the time and I cannot establish a pattern of when/why it does it. Sometimes it can be days between occurences, and other times it happens regularly. This week I have used the car every day and it didn't happen once until Friday, and then did it three or four times and then stopped again.

I have lived with this for a couple of months now, trying to establish a pattern, but would really like to sort this now......so any advice would be appreciated.
 
G
#3 ·
No, it bounces between around 1000rpm and 0rpm three or four times and then settles at about 700rpm - and has never cut out as yet.

Also just be looking through the previous owners paperwork and the air flow meter was replaced with a reconditioned unit in Sept 2009 (6k miles ago) when there was a "misfire under acceleration".
 
G
#5 · (Edited)
Thats the problem, there isn't one around here.......and the "dealer" isn't really a specialist, they sell lots of brands under one dealership (Ford, Mazda, Fiat, Alfa, Subaru etc)......wouldn't trust them with anything.

Just also noticed (as I am on the case now) that sometimes even when the revs are steady, the needle is moving a fraction (a couple of mm max) up and down.....but again not always.......in case this helps anyone with an idea of the issue ?
 
#7 ·
Hi, it sounds exacltly like the problem I had which turned out to be a sticking butterfly valve on the throttle body. I had a similar erratic idle that followed no discernable pattern.

I tried cleaning it in-situ following instructions that I found on this forum but that didn't help so I explored other possible causes. Eventually, I returned to the throttle body as the likely cause after months of frustration and this time changed it for a second hand one and sure enough problem fixed! With the part off the car I could feel it sticking as I moved the valve. It was very easy to replace, even for a complete novice like me.

Hope that helps!
 
G
#8 ·
Hi mate

Thanks very much for your post. I was starting to think I was the only one with this issue, and feeling a little lonely :lol:

I will get onto this and see if it sorts the problem.

Cheers :thumbs:
 
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