Vibration at idle

blackout51

Original poster
Member
Oct 18, 2012
157
Idle is normal rpm, but when it's up to temp there's a vibration that shakes the emergency brake and is felt through the whole truck, it feels like when you hold the window switch up and you get that electric load on the motor. Could it be the battery?
 

Wooluf1952

Member
Nov 20, 2011
2,663
Milwaukee, Wisconsin
If it's worse in Drive or Reverse and gets better in Park or Neutral, it could be the motor mounts.
 

blackout51

Original poster
Member
Oct 18, 2012
157
Wooluf1952 said:
If it's worse in Drive or Reverse and gets better in Park or Neutral, it could be the motor mounts.

It gets slightly better in neutral for a few seconds then is almost the same as in drive, but I know I need to change the mounts soon I'm just wondering if this vibration is a symptom of them
 

CaptainXL

Member
Dec 4, 2011
2,445
I would say it is not a symptom. Mainly due to the fact that it runs fine when cold running in open loop. You are probably running too rich due to the exhaust leak as it will have an effect on the O2 sensor.
 

blackout51

Original poster
Member
Oct 18, 2012
157
CaptainXL said:
I would say it is not a symptom. Mainly due to the fact that it runs fine when cold running in open loop. You are probably running too rich due to the exhaust leak as it will have an effect on the O2 sensor.

I mean its not, as soon as it warms up it does this, it's more once it hits 600 rpm it does it, at 650 it goes away
 

The_Roadie

Lifetime VIP Donor
Member
Nov 19, 2011
9,957
Portland, OR
Why do you think you need to replace the mounts except for the 10 Hz idle vibration problem? Are they visibly collapsed or deteriorated? You can try prying up on one engine bracket at a time with a crowbar to see if the vibration changes.
 

blackout51

Original poster
Member
Oct 18, 2012
157
the roadie said:
Why do you think you need to replace the mounts except for the 10 Hz idle vibration problem? Are they visibly collapsed or deteriorated? You can try prying up on one engine bracket at a time with a crowbar to see if the vibration changes.

Well I really don't know what a 10hz vibration feels like. But I replaced them with dea mounts back in September and they just look really bad which I know isn't any indication but I knew I would be putting gm mounts in when I got a chance. But where would I put the prybar to get any leverage on it? It looks like a difficult area to get anything into
 

CaptainXL

Member
Dec 4, 2011
2,445
We can really only recommend AC Delco mounts. If you have any other brand they should be replaced. Just too many horror stories using aftermarket mounts. You should also repair the exhaust manifold and replace the 02 sensor at the same time. After those are taken care of then you can proceed with troubleshooting to avoid confusion.
 

blackout51

Original poster
Member
Oct 18, 2012
157
CaptainXL said:
We can really only recommend AC Delco mounts. If you have any other brand they should be replaced. Just too many horror stories using aftermarket mounts. You should also repair the exhaust manifold and replace the 02 sensor at the same time. After those are taken care of then you can proceed with troubleshooting to avoid confusion.

I have replaced both o2 sensors already and I don't think there is anything wrong with my exhaust manifold, I'll have to take the sheild off and inspect it but I don't hear any leaks or smell any leaks
 

CaptainXL

Member
Dec 4, 2011
2,445
blackout51 said:
I have replaced both o2 sensors already and I don't think there is anything wrong with my exhaust manifold, I'll have to take the sheild off and inspect it but I don't hear any leaks or smell any leaks

Im sorry. I thought you noticed smoke coming out the exhaust manifold.
 

blackout51

Original poster
Member
Oct 18, 2012
157
CaptainXL said:
Im sorry. I thought you noticed smoke coming out the exhaust manifold.

Oh, no I havent had that. The manifold seems fine as far as I can tell, I'd think a crack would be fairly noticeable if it was there
 

blackout51

Original poster
Member
Oct 18, 2012
157
So a new development is that when I floored it today i couldn't get the rpms to go over 5k, I know my cat is bad because I have the bad cat code, and I'm waiting on getting a new one installed until I get a chance to go to a shop. But could this be part of the idle too?
 

blackout51

Original poster
Member
Oct 18, 2012
157
the roadie said:
Don't think so. In neutral or park, you can't rev that high anyway because of the rev limiter. You did the 5K in gear?

Oh no, this was getting on the highway, I know trying that would be a bad idea
 

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