Vibrations maybe bad motor mounts

[wsteele]

I’m using OBDLink app and I couldn’t find Live Data or anything about misfires except in the emission test section where it has a check mark next to misfires.
I did ran the real time monitor and at idle RPM fluctuates between 600 and 670, saw 700 once. Is that ok? I can feel vibrations through break paddle when it goes through fluctuations.

Did you decide to install those new mounts?

I am not familiar with ODBLink, so I can't tell you where to look in the app to display the misfire data. My cheapo $20 ODB reader dongle and free IOS app displays it. So if you find out yours won't display it, maybe consider upgrading/downgrading to a reader and app that will show it.

The idle RPM excursions seem high. When my engine is cold, it fluctuates at idle as much as 20 RPM, once it warms a little, it rarely changes more than 10 RPM.

 

[sctrl]

Did you decide to install those new mounts?

I am not familiar with ODBLink, so I can't tell you where to look in the app to display the misfire data. My cheapo $20 ODB reader dongle and free IOS app displays it. So if you find out yours won't display it, maybe consider upgrading/downgrading to a reader and app that will show it.

The idle RPM excursions seem high. When my engine is cold, it fluctuates at idle as much as 20 RPM, once it warms a little, it rarely changes more than 10 RPM.

Got H3 mounts. Gonna install this week if I have time. It’s RWD so gonna attempt to DIY.
Which app are you using?

 

[wsteele]

Got H3 mounts. Gonna install this week if I have time. It’s RWD so gonna attempt to DIY.
Which app are you using?

I use a free app called Car Scanner. I did do the lifetime premium upgrade for like $8 that lets me display unlimited parameters at the same time, but the free version works fine as well.

I also have a Tech 2 clone for anything more serious than viewing status.

 

[sctrl]

Feel like complete noob. Was gonna do driver side motor mount myself. Took out all bolts. What a pain the ass. Tried to lift the engine using jack and block of wood under the oil pan. But it seems like the engine is lifting with the car. I don’t get it. I probably pushed it up couple of inches but no space between motor mount and frame or engine. All going up together. What am I doing wrong? YouTube made it look so easy haha

 

[gooffeyguy]

Feel like complete noob. Was gonna do driver side motor mount myself. Took out all bolts. What a pain the ass. Tried to lift the engine using jack and block of wood under the oil pan. But it seems like the engine is lifting with the car. I don’t get it. I probably pushed it up couple of inches but no space between motor mount and frame or engine. All going up together. What am I doing wrong? YouTube made it look so easy haha

When I did mine I put the jack under the drivers side exhaust right where it transitions from vertical to horizontal. There's a catalytic converter end right there so it sorta rested in the cup shape of the jack

 

[sctrl]

This message goes out to y’all who answered my questions and helped first time Yukon owner.
I finally finished motor mounts swap. Let me tell you, it was a pain, especially passenger side. I don’t know how many extension combos I used to ge those bolts, but in the end it all worked out.
Great news is my “rough idle” is gone! And the car drives so much smoother!
I’ll give it few more days to get used to but overall this was a great success, even my gf noticed the difference.

 

[OR VietVet]

Great. Glad it worked out for you and you stuck with it to "Git 'er done"!

In a couple days or so, when you are very confident the repairs have held, please go to your #1 post for this thread and at the top right you will see 3 dots and a down arrow. Click there and then click on "edit thread" and then you can go to the thread original title and you can type in the word SOLVED and that will catch the eye of anyone that scans across it and will read the entire thread to see how the diagnosis and repair process went and that will help other members on their rigs. Please......

 

[Rocket Man]

This message goes out to y’all who answered my questions and helped first time Yukon owner.
I finally finished motor mounts swap. Let me tell you, it was a pain, especially passenger side. I don’t know how many extension combos I used to ge those bolts, but in the end it all worked out.
Great news is my “rough idle” is gone! And the car drives so much smoother!
I’ll give it few more days to get used to but overall this was a great success, even my gf noticed the difference.

That's awesome, good news!

 

[sctrl]

Did you decide to install those new mounts?

I am not familiar with ODBLink, so I can't tell you where to look in the app to display the misfire data. My cheapo $20 ODB reader dongle and free IOS app displays it. So if you find out yours won't display it, maybe consider upgrading/downgrading to a reader and app that will show it.

The idle RPM excursions seem high. When my engine is cold, it fluctuates at idle as much as 20 RPM, once it warms a little, it rarely changes more than 10 RPM.

So finally bought the app and ran the live monitor while driving. No misfires while idling. But noticed occasional misfire while driving, always two at a time, just random cylinders, 2, then 1, then 8, then 4. I drove for 15 min maybe. Is this normal?

 

[gooffeyguy]

Random misfires is usually due to a vacuum leak, but odd that it doesn't do it at idle