Car Idles High When The Car Is In Neutral

[muddfisher85]

So I finally put my car on the road today and I noticed that if I put the car in nuetral and let the clutch out the car idles at anywhere from 1500 to 2000,but with the clutch in it idles normal 800-900. Sometimes when you start it when its warm the idle will just keep going up and down between 1500 and 2000. I held a dollar bill to the exhaust just to see what was happening when it was going up and down. I noticed that when it went up and came back down that it sucked the dollars inwards of the exhaust. Someone told me that it was a sign of a bad valve or head gasket. Any advice would be great

The car does have a stage 2 clutch and lightened flywheel but they were previously installed when I got the car.

 

[crusher966]

Check your pcv valve. Should be on the back left on the cylinder head unscrew it and shake it. If you dont hear anything replace it.

 

[Skunkcar]

if youre going to take your pcv valve off you might as well get a new one anyways, for about $3.59

I changed mine yesterday, just got the car recently after it had been sitting for over a year. When I shook it it sounded fine but there was plenty of gunk inside.

maybe your valve is fine.

im interested in this though, because im idling at about 12-1400. Wasnt too concerned though since it was the first time she'd been started in so long, figured id get to it eventually.

 

[spartan69x]

my tsi did the same thing, but on really hot days it was even worse, granted it was an auto. I had always figured tps or something of the sort.

 

[And_44]

I just recently bought my TSi as well 1990 manual. Last week I changed plugs and used a timing light to adjust my timing to 5BTDC was at almost 20;(. I got it to idle nicely at 850-950 with and with out clutch engaged. Well today I patched a hole in my exhaust manifold, removed my emission vacuum lines according to the 0$ mod, and capped an open line in my intake that went to a non exsistant BCS. Now I got an idle of 1200-1300. I believe it may have to do with my resetting my ECU (had to remove battery to get better access to vacuum lines) Gonna drive it for a few days and see if it resets the idle if not gonna adjust my timing again, then if that doesn't work gonna adjust my BISS. And the vacuum lines that are left I replaced with new. And no boost leaks in intake detected.

Also removing the vacuum lines for emissions and capping that line my idle is really really smooth now

 

[muddfisher85]

I had already replaced the pcv valve but I went ahead and changed the hose. It didnt make any difference. When driving today my clutch pedal sort of got stuck half way down until I pulled up on it with my foot. There was a few wires that looked like they might have been in the way but there is no resistance on the pedal until half way down so I guess I need the adjust it. It was weird though I was like damn got the car on the road for a day and already broke it. Now I do have a check engine light on it says evap emission purge vavle C fault. Would this cause this ?

 

[And_44]

Vacuum leak to the purge valve or it may be faulty? May be opening at some points and releasing the gas vapors into your intake making it jump rpms? From my understanding the valve sense's the built up pressure from your gas tank and releases the excess into your intake to burn usually at 3k rpms when turbo kicks in. If it's malfunctioning could be staying open and the vacuum pressure causing a negative pressure and just sucking gas vapor. And your clutch... well I don't know that system very well. But it sounds as though it just needs an adjusting or a good bleeding(air stuck in line). Not sure if they run off vacuum lines as the emission equipment but both could be connected.

P.S. I believe my idle problem was caused by me fumbling around the back of engine and may of just messed with my Throttle cable;(

 

[crusher966]

Honestly with that code id check your EGR solenoid. When the power grounds it can often lead to that code. Follow the wiring and look for a faulty point in wiring.

 

[OneSlowL36]

All good replies, I'd like to add, maybe check the adjustment of the throttle cable on the upper intake plenum. Or the EGR hose, that thing gets a lotta heat and is prone to cracking.

 

[muddfisher85]

I am going to bleed the clutch it tommorrow if I get a chance just been really busy lately. But Im sure there is air in the lines you can feel it in the pedal. Ill check the throtle cable and egr hose and wires too thanks

 

[JDMTransfer]

also check your I.A.C mine did the same thing and it fixed it after 5 minutes or so idling

 

[darkstar5456]

mine does the same thing but only somtime when i push the clutch in it would idle around 2000 and i would tap on the gas and it would even out.i do it my i.a.c is done thats why it is idle surging

 

[muddfisher85]

Come to find out my clutch fork was bent not releasing the clutch all the way and was causing the lightened flywheel to expand when it got hot from the clutch draging. That caused the car to stahl out when you would come to a stop after a short drive. Also ruined my act 2600 and lightened flywheel.