erratic idle and stalling

**ben_al69** · 28-06-2010, 08:12 PM

hi all

trying to find out what is wrong with our golf. it idles up and down every now and then and stalls at lights (never whilst actually driving) and wont start for a couple of minutes. can anyone tell me what could be wrong as i would rather fix it than pay a dealer or specialist those stupidly huge prices.

thanx

**brodzta_GTI** · 28-06-2010, 08:32 PM

Gday mate,

Is it manual? auto? what engine? how many kms? how often is it serviced? what fuel do you use? How long has it been happening? does it happen when hot or cold? Does the coolant gauge move erratically? These are all things that need to be answered before even trying to diagnose the fault.

I know it seems like a blunt response but these are questions i ask of customers/service advisors on a daily basis. ( i work at a vw dealership )

**Golf Loon** · 28-06-2010, 08:39 PM

Yup would help if you told us what engine.
Its common to be a vacuum leak on a Mk4. Take the engine cover off and check all the plastic pipes that come from the oil brether and go to the intake pipe.

**ben_al69** · 28-06-2010, 08:53 PM

Gday mate,

Is it manual? auto? what engine? how many kms? how often is it serviced? what fuel do you use? How long has it been happening? does it happen when hot or cold? Does the coolant gauge move erratically? These are all things that need to be answered before even trying to diagnose the fault.

I know it seems like a blunt response but these are questions i ask of customers/service advisors on a daily basis. ( i work at a vw dealership )

sorry guys. pretty crappy description. its manual, 1.6 base model 75kw, 203,000kms, serviced every 15,000 religiously, always use premium fuel, only been happening in the last month and only when at running temp, temp gauge does what it should.

**brodzta_GTI** · 28-06-2010, 09:14 PM

Righto

Theres 7 ,10mm nuts that hold the 2 engine covers ontop of the engine. undo these and remove the covers.

First. If you look at the intake pipe there should be a ( approx ) 50mm bit of hose that joins onto it from the oil filler neck.
There should also be another hose that comes off the oil filler neck and comes down and joins onto the crank case. check to see if these are broken (VERY COMMON )

Also, if your standing infront of the engine bay on the right hand side of the block, there'll be a black coolant block that has 4 outlets on it. There'll be a coolant sensor on the top. Check to see if the colour of the top section is black or green. If its black, get a new one ( is a known VW problem to fail ).

Start the vehicle and spray carby clean over all vaccum lines in the engine bay. ( this is to find any leaks, if the revs drop then pick up you know you've found a leak )

Maybe try removing the fuel filter and removing the contents onto a white rag. ( if there are any contaminets in the system they will show prominetly on the rag. Ive used this technique of Golf 4's before )

Failing those suggestions,

You could go to someone with a scan tool. It doesnt need to be a dealership, just any workshop that has a OBD-II compatible tool with the ability to read VW systems ( it just helps to go to a dealership as the techs have most probably seen the fault before and have all the information within easy reach/ can fix it really quickly )

Hope this helps

**ben_al69** · 28-06-2010, 09:22 PM

thanks heaps!!

looks like my day off work just got busy again.

i will try all of this and get back to you.

thanks again

**McCosker** · 29-06-2010, 09:02 AM

Check your MAF. unplug it, drive round and see if that fixes the problem.
If it does, remove the MAF and clean it up as best you can with some Electrical Contact Cleaner.
This should fix it for a while, but it will be on the way out if this is whats wrong with your car.
Atleast this is easy to do. only takes a few mins to check if its the problem.

hope you get it sorted soon.

**gavs** · 29-06-2010, 01:03 PM

Originally Posted by brodzta_GTI

Righto

Theres 7 ,10mm nuts that hold the 2 engine covers ontop of the engine. undo these and remove the covers.

First. If you look at the intake pipe there should be a ( approx ) 50mm bit of hose that joins onto it from the oil filler neck.
There should also be another hose that comes off the oil filler neck and comes down and joins onto the crank case. check to see if these are broken (VERY COMMON )

Also, if your standing infront of the engine bay on the right hand side of the block, there'll be a black coolant block that has 4 outlets on it. There'll be a coolant sensor on the top. Check to see if the colour of the top section is black or green. If its black, get a new one ( is a known VW problem to fail ).

Start the vehicle and spray carby clean over all vaccum lines in the engine bay. ( this is to find any leaks, if the revs drop then pick up you know you've found a leak )

Maybe try removing the fuel filter and removing the contents onto a white rag. ( if there are any contaminets in the system they will show prominetly on the rag. Ive used this technique of Golf 4's before )

Failing those suggestions,

You could go to someone with a scan tool. It doesnt need to be a dealership, just any workshop that has a OBD-II compatible tool with the ability to read VW systems ( it just helps to go to a dealership as the techs have most probably seen the fault before and have all the information within easy reach/ can fix it really quickly )

Hope this helps

Awesome, I will do this too as I have an erratic idle which comes and goes too

**ben_al69** · 29-06-2010, 03:07 PM

update

i took the car in to a mechanic today. he connected it up to his computer and it comes up with coolant temp sensor failing. something i should have picked from the start since i noticed the smell of fuel when trying to restart the car after it stalls! anyway, its getting replaced on saturday morning so i will let you all know if that solves the problem.