On my 2001 Ford focus, 1.6L 5 door station wagon i noticed today (in the busy auckland motorway traffic) a idle problem. During the stop go stop go traffic, i would speed up to say around 30-40kmh, and as i slow down to at exactly 20kmh, my idle would go crazy and keep fluctuating between 400rpm - 1200rpm (you can even see the head lights go dim and bright). The idle sometimes drop so low that the engine shudders and almost stalls.
This idling problem i only noticed today and would happen on about 80% of the time during the stop go stop go traffic jam home from work today.
Does anyone know what the problem may be! The car has done 171,000km so it is a fairly high milage engine but has been serviced regularly!
My initial thought was some ignition problem but the engine doesn't missfire during high speeds or when i accelerate.
Could it be some sort of vacuum leak or a problem with the idling valve or maybe even the ecu!
any help would be greatly appreciated,
Cheers, Jun.
unclejake,
May 24, 4:30pm
It could be the AFM on the way out
rob_man,
May 24, 4:44pm
Not coinciding with the braking!
superiornz,
May 24, 4:47pm
Rob_man, when i brake, the car slows down = engine slows down = revs drop so it kind stops the fluctuating.
It seems to only do it when the cars slowing down by it self (no brakes applied) and as it slows down pass 20kmh it starts fluctuating
rob_man,
May 24, 4:49pm
Ok, thought the booster may have had a problem.
bdogg1,
May 24, 5:15pm
Check the water level in your radiator. MY toyota corolla used to do this and someone told me it was the engine trying to get more water in. And yes, it was low and it did work.
superiornz,
May 24, 7:16pm
I think i spotted the problem or heard the problem.
Vacuum leak. With the bonnet up and engine idling, i can hear a moderately loud pshhhhhhhhhhhhhh air leak from somewhere (cant determine which hose and with poor lighting at night).
Just wondering, is it ok to drive to work and back till the weekend or will i be risking the engine running too lean and over heating! I actually notice the termperature stays cold the whole time as if the ecu is trying to counter attack the extra air and pumping more petrol in.
andy61,
May 24, 7:50pm
Sounds likes the thermostat needs replacing for a start.
bae13,
May 24, 7:53pm
get an auto sparky to check the charge rate, these are prone to over charging, this causes alot of driveability issues/ weird lights coming on, the vehicles i have seen have all had different symptoms, to lights coming on dash, transmssions changing up and down erratically, idle issues. over fuelling and smelling of rotton eggs out the exhaust.
for_an_angel,
May 24, 7:56pm
Theres ya problem right there. Sounds like a faulty temp sensor or air lock in cooling system or low water level.
superiornz,
Apr 1, 2:46am
the vacuum leak is definately coming from the near the engine block where the four HT leads run on top. I tried using carb cleaner to listen for idle changes but cant spot it (also im too scared to spray too much incase it ignites on fire :P).
I did squeeze the fairly large hose (about half inch or so thick) that comes from the engine block to the air filter, i think its one of those recycle hoses to reduce emission (some sort of breather hose). anyway, when i squeeze as hard as i can on this hose, thepshhh noise dramatically reduces (i cant fully get rid of the pshh noise, maybe i cant squeeze hard enough). But would this be where the leak is coming from ! visually, the hose looks fine with no cracking etc.
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