F~ing vibration!

[demea]

What are some of the known issues that would make your car vibrate/bad idle?
I've read the snub mount could, but list some KNOWN fixes for this because its driving me up the wall

It happens @ idle whether its in gear or in park. Sometimes, the car feels like it want to stall when slowing down at a light as well...but never does. Just kinda dips below the 800 rpm mark then comes right back.

• Car has 53K
• GIAC K03FX
• NGK BKR7E plugs (about 500 miles on them) gapped to .032
• 4 fresh factory coilpacks (about 2K miles ago)
• Forge SPLT-R
• Magnaflow 14851 mufflers with custom piping up to the Y.
• Due for an oil change/seafoam in 1000 miles (never seafoamed the car, fyi)

I dont have a boost gauge, so I dont know for sure its holding or leaking...

Thanks in advance

[coowhip]

I would say a busted snub or other mount...may have a vacuum leak as well. Get a boost/vacuum guage.

[demea]

Get a boost/vacuum guage.

I'm certainly overdue for one

[widgget]

the easiest thing to do is to try adjusting the cup the snub mount sits in. takes a few minutes and is likely the cause of the vibraition.

[absolutegtr]

I would say snub.....


As for your spark plugs, they should be gapped to .028

[demea]

I would say snub.....


As for your spark plugs, they should be gapped to .028

Yeah, I'm going to redo them to .028.

Thanks fo' the suggestions

[demea]

Is this a good example of how to adjust / replace a snub mount?

[widgget]

Is this a good example of how to adjust / replace a snub mount?

yes. just loosen the bolts shown in step 6, then jump to step 8 and follow the instructions.

[A4 Moda]

definitely a boost leak or vacuum leak.

Check the L shaped hose at the back of the block. That one usually busts first.

[a4wd]

what should the boost gauge read when at idle? I usually get -21mhg when I am @ idle. Is that normal? I am surprised I havent had any boost leaks yet *knocks on wood*and just want to better prepare myself.

[A4 Moda]

Yes normal idle without a/c should be 18-20 and some have seen 21-22

With A/C 12-15 mm/hg

That's your vaccum BTW not boost, Just FYI

Stock programming should allow peak boost at 7-8 psi,.
Chip Programming should allow 20-22 psi peak.

GL

[sloweryucf]

Same problem as you man. Still have yet to check for leaks. Annoying as all hell.

[B6JoeS4]

i have the same problem in my 3.0. do you guys think its my mounts?

[NyteEscape]

if it was a solid idle rpm that it vibrates at, i would've said snub. but since you said it dips below 600, i would agree with these guys that it's a vacuum leak.

[demea]

if it was a solid idle rpm that it vibrates at, i would've said snub. but since you said it dips below 600, i would agree with these guys that it's a vacuum leak.

It is a solid idle vibration. The normal idle is 800 rpms.
Sometimes, though (not all the time), it'll dip below 800 rpms when I'm slowing down to stop at a light or something (maybe to like 700??) and then go right back to normal. It dips for a split second, then goes back to a nominal 800 rpms.
The vibration, though, is in P, D or R and is present @ idle.

I'm going to check for vacuum leak this weekend as well as check my snub mount and regap my plugs to .028. I have to adjust my DV anyway., so I'll be under the car already.

[absolutegtr]

It is a solid idle vibration. The normal idle is 800 rpms.
Sometimes, though (not all the time), it'll dip below 800 rpms when I'm slowing down to stop at a light or something (maybe to like 700??) and then go right back to normal. It dips for a split second, then goes back to a nominal 800 rpms.
The vibration, though, is in P, D or R and is present @ idle.

I'm going to check for vacuum leak this weekend as well as check my snub mount and regap my plugs to .028. I have to adjust my DV anyway., so I'll be under the car already.

If the idle ever dips....even ever so slightly, that means a vacuum leak (most likely a very small one!)

[sloweryucf]

Damn vaccum leaks!

[ApexIt]

im having a very similar problem. The car vibrates a little at idle, D and R but its not all the time. Sometimes its super smooth and other times its just annoying. I was thinking it was the sparks but i guess i should check for boost leaks. Anyone have a diy on how to check or is there one in the diy section here already?