Vehicle feels like it is going over bumps on slow coast from a dead stop

[mdmcinti]

How did you inspect the trans and motor mounts? They can LOOK fine but could be separated and you will not see it till you try to lift the trans/transaxle and see if separates. If any of the mounts are compressed/collapsed enough, the metal can hit and cause a feeling of a vibration.

I just looked at it lol. I noticed the idle is a little rougher in park. But I am trying to rule out worn spark plugs for that case. How bad should vibration feel on a worn motor mount? I know I should do the pop the hood and see how bad the motor jerks test.

 

[mdmcinti]

You can have good thickness on brakes but if you are in an area where salt is used on the road, that can wreck havoc on caliper slides and hardware and such, 97% highway driving or not. I doubt the brakes are the problem but I was giving options.

Nevada uses a salt brine on their roads. We did drive it on the highway during all the snow we got. The calibers have some rust on them. More than my previous all AZ their whole life vehicles have ever had.

 

[Doubeleive]

are you feeling this thru the brake pedal? or is the whole truck making a vibration

 

[OR VietVet]

Yep, I live in Oregon and we don't deal with rust here. I was in heaven when I ran shops and moved from salt on the roads, KC, Mo., to Eugene, Or., no salt on the roads.

 

[mdmcinti]

are you feeling this thru the brake pedal? or is the whole truck making a vibration

Its through the whole truck. My foot was not on the brake at all.

 

[Bill 1960]

I’m thinking a slight misfire or stumble at idle. Disappearing under normal acceleration.

I’d try duplicating the conditions with someone else behind the wheel while you walk alongside and watch and listen. A misfire you can hear at the exhaust or if you leave the hood up you’ll probably see the engine shuddering a bit.

 

[mdmcinti]

Yep, I live in Oregon and we don't deal with rust here. I was in heaven when I ran shops and moved from salt on the roads, KC, Mo., to Eugene, Or., no salt on the roads.

Only in one place in Oregon they salt because that pass gets really bad weather.

 

[Doubeleive]

Its through the whole truck. My foot was not on the brake at all.

I would chock the front wheels and jack up the rear wheels and put it on jack stands and then start it up and put it in 1st gear and see if can hear any noise from the rear end or transmission, apply the brakes if needed to keep the speed slow. If it's not the abs and the brakes are not worn down to nothing then it may be something in the drivetrain. maybe a bent wheel? (just something to check)

 

[mdmcinti]

I’m thinking a slight misfire or stumble at idle. Disappearing under normal acceleration.

I’d try duplicating the conditions with someone else behind the wheel while you walk alongside and watch and listen. A misfire you can hear at the exhaust or if you leave the hood up you’ll probably see the engine shuddering a bit.

That is one of my guesses too because I know those plugs need to be changed. We will find out if that was the cause in a few months. I have a baby on the way soon so I don’t have time right now.

 

[mdmcinti]

I would chock the front wheels and jack up the rear wheels and put it on jack stands and then start it up and put it in 1st gear and see if can hear any noise from the rear end or transmission, apply the brakes if needed to keep the speed slow. If it's not the abs and the brakes are not worn down to nothing then it may be something in the drivetrain. maybe a bent wheel? (just something to check)

Would a bad u joint cause this?