High Idle Revs

[fsgti]

I have noticed the car has some idle rev issues. This generally occurs once the car is warm and up to temperature.

The car idles at around 1k rpm and sometimes momentarily revs hang at around 1.5k then drop. Whenever I put the car into neutral and slow down to a halt, the revs also hang then as high as 1750 rpm and then only drop to around 1k after coming to a complete stop.

I have changed the PCV with its gasket.

Any Ideas?

Thanks

[GVK]

99% an air leak , check all the vac lines and pcv upper and lower hose, the brake booster hose etc

[pudding]

What part number front PCV did you use?  One of the earlier revisions requires a check valve in the rear cam cover outlet.

If not that.....as above, retrace your steps and look for obvious air leaks.

If it's manual, do a fault code scan to see if the clutch switch is faulty.

[fsgti]

What part number front PCV did you use?  One of the earlier revisions requires a check valve in the rear cam cover outlet.

If not that.....as above, retrace your steps and look for obvious air leaks.

If it's manual, do a fault code scan to see if the clutch switch is faulty.

Link to the ebay listing : https://www.ebay.co.uk/itm/255651139529

If it's the manufacturer part number you are referring to then its : 06F129101
OE/OEM part number : 06F129101E/06F129101G 06F129101P

^ that's whats given on listing.

Do you have any recommendations for good quality but affordable scan tools? I'm talking sub £100. Have heard some of the super cheap ones can damage software.

EDIT: Just got it scanned and I get:
P0171 - System too lean
P0441 - Evaporative emission control control system incorrect purge flow

[fsgti]

99% an air leak , check all the vac lines and pcv upper and lower hose, the brake booster hose etc

Sorry if this is a stupid question but how would I check for a leak? Just listen for hissing air or ...?

[GVK]

Listen for hissing, spray soapy water on the lines and check for bubbles when running, or get a suitable garage to do a smoke test.

Edit - also spray around inlet/vac hoses with an accelerent such as brake parts cleaner, if the brake cleaner gets sucked in, the engine note will alter.

[fsgti]

Listen for hissing, spray soapy water on the lines and check for bubbles when running, or get a suitable garage to do a smoke test.

Edit - also spray around inlet/vac hoses with an accelerent such as brake parts cleaner, if the brake cleaner gets sucked in, the engine note will alter.

Nice one, will give that a go.

[pudding]

What part number front PCV did you use?  One of the earlier revisions requires a check valve in the rear cam cover outlet.

If not that.....as above, retrace your steps and look for obvious air leaks.

If it's manual, do a fault code scan to see if the clutch switch is faulty.

Link to the ebay listing : https://www.ebay.co.uk/itm/255651139529

If it's the manufacturer part number you are referring to then its : 06F129101
OE/OEM part number : 06F129101E/06F129101G 06F129101P

^ that's whats given on listing.

Do you have any recommendations for good quality but affordable scan tools? I'm talking sub £100. Have heard some of the super cheap ones can damage software.

EDIT: Just got it scanned and I get:
P0171 - System too lean
P0441 - Evaporative emission control control system incorrect purge flow

Well if that ebay listing is to be believed, it reckons it's 06F129101R, which is the correct part. 

It seems like that unplugged hose in your other thread could be the cause of your issues.......and going by the P0441, the hose is probably related to the carbon can.  Why anyone would just disconnect that and leave it dangling about like a pair of sweaty plums.....

[fsgti]

What part number front PCV did you use?  One of the earlier revisions requires a check valve in the rear cam cover outlet.

If not that.....as above, retrace your steps and look for obvious air leaks.

If it's manual, do a fault code scan to see if the clutch switch is faulty.

Link to the ebay listing : https://www.ebay.co.uk/itm/255651139529

If it's the manufacturer part number you are referring to then its : 06F129101
OE/OEM part number : 06F129101E/06F129101G 06F129101P

^ that's whats given on listing.

Do you have any recommendations for good quality but affordable scan tools? I'm talking sub £100. Have heard some of the super cheap ones can damage software.

EDIT: Just got it scanned and I get:
P0171 - System too lean
P0441 - Evaporative emission control control system incorrect purge flow

Well if that ebay listing is to be believed, it reckons it's 06F129101R, which is the correct part. 

It seems like that unplugged hose in your other thread could be the cause of your issues.......and going by the P0441, the hose is probably related to the carbon can.  Why anyone would just disconnect that and leave it dangling about like a pair of sweaty plums.....

Hmm, I'm pretty sure the charcoal cannister only is meant to have 2 hoses connected to it which it does. A few others thought the hose might be for a boost gauge.

Side note: I also have p2196 code which indicates a rich mixture in bank 1 sensor 1 (pre-cat) I'm a little confused as to how I can have a lean code and a rich code.

[pudding]

Just seen the other pic and that's definitely an old boost gauge hose or something.

You need to see what the long and short term fuel trims are, if your scan tool can show them.