MK4 Under revs

[X_Lollypop_X]

Dont know if this is a common problem or anything, but since its been uber cold my car has been under revving.......sometimes it does it sometimes it doesnt. Sometimes it will drop right down light it feels it wants to stall and then picks back up, but then sometimes it will rev quite hard on its own if Im just sat with the engine on and then drop right down.....any ideas? please help

J
xx

 

[whittle123]

does the revs jump up and down on idle just every now and again (lasts for 30 secs and goes back to normal) e.g. 750rpm-400rpm-750rpm-400rpm as if its gonna stall????

 

[X_Lollypop_X]

only when im idle and the revs go down and stay down or jump up then go back down but dont go in stages just goes right down

J
xx

 

[whittle123]

sounds like lambda sensor but there would fault codes....hmmmmm. any warning signs on dash???

 

[X_Lollypop_X]

nope nothing comes up on the dash, I had heard that the air intake on the mk4's werent good and that it coulld be because of that, but i have no clue so i jsut smiled and nodded lol

J
xx

 

[whittle123]

but i have no clue so i jsut smiled and nodded lol

lol

erm not sure then, could just be sum "dirty" fuel from like a supermarket petrol station??

could put some redex in with ur fuel next time, maybe sumone else here could enlighten you????

appologies 4 nt being of any help x

 

[X_Lollypop_X]

I use premium unleaded from Shell lol I wont use anything else

Thank you anyways

J
xx

 

[Danneh]

Does it do this when you first start it for a while? Say for 10 mins or so then goes away?

Say if you've been driving for a bit, does it stop?

My old car did this in very cold whether on start up, it may be the choke? My old car used to be funny because of that sometimes.

It could also be a dirty sensor as already said.

 

[X_Lollypop_X]

sometimes does it when I first start it up, sometimes does it after ive been driving a bit

J
xx

 

[Danneh]

Does it do it when the car is fully warmed up to running temperature?

If it only does it when its warming up and starting, it may be choke. If it does it at any time, I think it could be something like a faulty sensor.

Thats all I can think of, sorry if it does not help

Dan x

 

[Poverty]

1.2 or 1.4?

 

[X_Lollypop_X]

Thanks for the help dan and its all the time, warm or cold and its a 1.2

J
xx

 

[Danneh]

When did you last have it serviced?

It sounds like it is time for a major service such as - spark plugs, coilpacks, fuel injection service, clean the throttle bore, idle air passages and idle air control motor. Also replace the fuel filter and air filter.

I don't mean do all of those, but a good service should do the trick. A good clean out of fuel/air filters, spark plugs etc should clear the problem.

If you've had a service recently... I'd take it to the dealer or indy and have a look at the sensors. Possibly the MAF?

 

[bertrum]

The 1.2 doesn't have "spark plug wires" (lol HT leads) but they have coilpacks. I would suggest one of these has gone, but you would have EML on the dash. Try running some redex injector cleaner through it.

R
xx

 

[Danneh]

The 1.2 doesn't have "spark plug wires" (lol HT leads) but they have coilpacks. I would suggest one of these has gone, but you would have EML on the dash. Try running some redex injector cleaner through it.

R
xx

lol. I'm not really used to Ibiza's I'm getting to know them better though. Hopefully I am getting a 1.9 TDI 130 soon.

 

[X_Lollypop_X]

I took it back to where I bought it from a few weeks after I had it because one of the lights had condensation in it and the spanner was on the dash when I bought it and they done a full service and stamped the book and everything.....ill try that redex and see if that works, it doesnt do it all the time just now and again, itsonly nearly cut out once but i jsut put my foot on the acelorator and it was fine (cant spell today)

Will try that and give it a go, i hope its nothing to do with the coil pack I replaced the one in the pug twice when i bought it because it was misfiring

J
xx

 

[bertrum]

Id prefer coilpacks than anything else to be fair. Cheap and easy to replace (there's three of them btw!)
Get it scanned with vag-com for faults.. afterall, it might not be them and could be a sensor!

R
xx

 

[X_Lollypop_X]

Will do thank you

J
xx