Hi all,
Just wondering if anyone can shed any light on this one for me please. MK2.5 1.8l
Two main symptoms (both happen together, rarely individually):
1) Car sometimes doesn’t idle properly (revs drop low), sometimes catches, sometimes cuts out, unless I keep a bit of throttle on
2) Even when driving, car judders/feels like something is trying to brake the engine but only for half a second or so. Tends to be worse at low rpm/throttle
The problem is intermitent, both in the long term (won’t happen at all one week but then 2 days running) and short term (i.e. not at every traffic light during a drive).
Battery recently changed, did this before and after. May be in my head but seems to happen more when it is cold/winter? But when it happens, even when the engine is warm it will continue.
Any help much appreciated!
Thanks,
You’ll get a better chance of solving it by stating which model/engine you have.
Doh!
It’s a MK2.5 1.8l
This car has onboard diagnostics - have you plugged a code reader into the OBDII port under the dash by the driver’s right knee to check for error codes.
Yes, sorry forgot to mention.
No fault codes triggered and no dash warning lights etc (other than when revs drop to like 200rpm)
Ummhhh - sounds more like a fueling issue rather than ignition misfire?
MAF, ecu, crank sensor, possibly throttle body.
Beginning to feel that OBD on these cars is next to useless in a lot of cases!!
+1 for MAF being a possibility, for the sake of a fiver it’s worth using some MAF cleaning spray because this has solved rough idle issues for me on a few occasions (on various cars).
Maybe also run some redex through the fuel system (again for the sake of a fiver)?
Thanks all, will give the MAF a go. It does have a K&N induction on the car and heard that can cause problems with the MAF. Got a fuel filter I’ve been meaning to put on for a while too so will do that at the same time.
If that doesn’t help will have a look at the other things mentioned here. Will let you know how I get on.
Cheers!
So little while later, MAF cleaned but still no help.
Much worse in the damp cold today. And at exactly the same time as a dip in revs whilst idling was a squealing noise. Happened a couple of times.
After driving for 20 mins, the car idled fine (didn’t cut out) for a good 15-20 mins until I switched it off. In the first 10 mins of driving it either cut out or nearly cut out about 5+ times.
Thinking it could be a belt/idler? Doesn’t always make noise though. Any ideas?
Cheers all!
For the benfit of others, I eventually changed the MAF which seems to have fixed the problem. No issues for a couple of weeks now!
Thanks all for the suggestions.
Hi
Can someone tell me what an OBD and MAF is, in case I have a similar problem
Thanks
OBD = onboard Diagnostics - OBDII port used to interrogate diagnostics for error codes - somewhere under dash on MK3.
MAF = Mass Air Flow, usually referring to the sensor. Not heard of too many problems with these on the MK3 but quite a well known cause of issue with earlier cars.