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Strange Vibration/Shake While Idling

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ChouDawg

Null
Location
San Diego, CA
Car(s)
2014 Subaru WRX
Hey all, so my 08 FSI GTI has a weird issue that hopefully someone can help me locate. So my car now has neuspeed p-flow, bsh forge dv relocate, and ATP 3" dp but I noticed this when the car was stock and still now.

Basically when I come to a stop and sitting at a light in neutral the tachometer doesn't show a rough idle but I'd say every 10 seconds or so the car will have a light shake front/back. Then back to normal then repeat. Car drives fine, no codes, etc. Car only has 15k miles.

I also noticed the brake pedal has a bit of a vibration to it too when pressed down again at idle or slow speed only.

Is this normal?

Thanks
 
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GodSquadMandrake

Radioactive Rotary Rocket
Location
Minneapolis
This is just a rough idle. Happens to my car too. It's likely that there is a lot of carbon built up inside the intake ports and valves. Probably in the combustion chamber too. And it's too bad but it requires manual cleaning. You can't just run seafoam through the engine and make it all shiny again. I'm planning on getting around to this soon since I just put the catch can on which should prevent the problem from worsening.
 
Deezz_Nuttz

Deezz_Nuttz

What's a User Title?
Location
So Cal
+1 for the intake hitting the brake booster...

as far as the idle shake, check your oil levels...
 
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GodSquadMandrake

Radioactive Rotary Rocket
Location
Minneapolis
Frankly a rock steady idle is scary to me. I'm used to a MKII with a lumpy cam that I could barely get to idle, a Subaru which is about as balanced as a fat man on stilts, and an RX7 which starts backfiring if it idles for more than a minute. I guess a stable idle is attainable, but it's just strange to me and makes me feel uncomfortable.
 
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ChouDawg

Null
Location
San Diego, CA
Car(s)
2014 Subaru WRX
Ill check the intake brake booster/reservoir. Anyone have a photo of what I'm looking for?

Also I'll check my oil too, the tach is rock steady at idle but as I mentioned there's a weird shake/pulse every few seconds.

I'm going to do an oil change soon too after final exams.

Thanks for the input guys if anyone has more feel free to post.
 
HereticByDefault

HereticByDefault

Go Kart Champion
Location
Chicago
ChouDawg said:
Ill check the intake brake booster/reservoir. Anyone have a photo of what I'm looking for?

Also I'll check my oil too, the tach is rock steady at idle but as I mentioned there's a weird shake/pulse every few seconds.

I'm going to do an oil change soon too after final exams.

Thanks for the input guys if anyone has more feel free to post.
Click to expand...

The brake resevoir is to the left of the battery, right under the bend on the intake. The brake booster is the black metal line running above the brake resevoir. im pretty sure the vibration at idle is normal. i have it and so does my friends GLI.
 
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GolfRS

Banned
Location
Europe-Greece
Once again,these threads pop up once in a while, only to be comforted by someone that "thinks" or "knows" this is normal...

BUT, after having replaced most of the critical parts (sometimes twice) i am still not convinced this is how the TFSI idles, mainly because it is progressively getting worse, and has an "on-off" quality to it, meaning sometimes its more observable, and sometimes its less...

Again, do a search about idle in the forum, and i've posted some contact info for a tech in the NY area that has been working with be online to try and solve this issue...
 
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ChouDawg

Null
Location
San Diego, CA
Car(s)
2014 Subaru WRX
I tried to better document the "shake" when sitting at a light today and it was barely noticeable, it isn't a huge shake or tremble its a very subtle short pulse that happens every few seconds when sitting at a light. Haven't had a chance to check the brake / intake contact but I'm pretty sure that might be the cause as I remember the P-Flo being very close to the brake reservoir. If the shake gets noticeably worse I'll do some more digging, for now I'll search for "idle"

How would I check if the PCV valve is leaking? The car only has 15k miles and was never chipped so I dont think it could've blown the PCV already. I did just recently get a Stage 1 trial flash running a forged DV and stock PCV but the trembling hasn't increased/worsened since then.
 
J

jliu

Passed Driver's Ed
Location
Richmond Hill
ChouDawg said:
I tried to better document the "shake" when sitting at a light today and it was barely noticeable, it isn't a huge shake or tremble its a very subtle short pulse that happens every few seconds when sitting at a light. Haven't had a chance to check the brake / intake contact but I'm pretty sure that might be the cause as I remember the P-Flo being very close to the brake reservoir. If the shake gets noticeably worse I'll do some more digging, for now I'll search for "idle"

How would I check if the PCV valve is leaking? The car only has 15k miles and was never chipped so I dont think it could've blown the PCV already. I did just recently get a Stage 1 trial flash running a forged DV and stock PCV but the trembling hasn't increased/worsened since then.
Click to expand...

Mine is very similar...however I only notice this very slight (you'll have to not move in my car to feel it) shudder when the engine is cold. So when I turn the car on in the mornings...they'll be 3-4 "shudders" as it idles a bit...then i dont notice it at all after. My car is a TSI and is bone stock.
 
brekdown29

brekdown29

J-O-O
Location
Phoenix
Car(s)
2016 Golf R FBO
Sounds like your just getting the mild surging that many of us report at idle...is it more noticable when you have the A/C on? If it's not a violent idle I'd say you can probably eliminate the main culprits of faulty pcv or bad coilpacks. How many miles are on your spark plugs?

There is a debate as to whether this is problematic or not. I personally don't believe it is because it's been happening with my car for as long as I can remember (thru new coils, plugs, dv's, and pcv systems) and it shows absolutely no other signs of fault or failure.
 
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GolfRS

Banned
Location
Europe-Greece
brekdown29 said:
Sounds like your just getting the mild surging that many of us report at idle...is it more noticable when you have the A/C on? If it's not a violent idle I'd say you can probably eliminate the main culprits of faulty pcv or bad coilpacks. How many miles are on your spark plugs?

There is a debate as to whether this is problematic or not. I personally don't believe it is because it's been happening with my car for as long as I can remember (thru new coils, plugs, dv's, and pcv systems) and it shows absolutely no other signs of fault or failure.
Click to expand...

So what if it's a faulty lifter...Ever think of that ?
 
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ChouDawg

Null
Location
San Diego, CA
Car(s)
2014 Subaru WRX
I took a look at the brake issue today, the P-Flo bend sits right on the brake fluid reservoir cap and totally explains my vibrating brake pedal. Anyone have a fix for this?

Just installed my newsouth boost gauge so I'll see how it idles and check for any leaks etc. I'm probably going to get a catch can next so I can rule out the PCV. Everytime now when I try to notice it I realize it's pretty much very very minimal which is definitely a good sign
 
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