Drivetrain Vibration when Cold

[rhobere]

95 4Runner, SR5 V6 with Manual Trans. ~180k miles.

So I had a problem start yesterday that I haven't experienced before and didn't see anything on the forum that fit my issue so hopefully not a repost.

When I start my car after sitting overnight, I get a pretty nasty vibration that can be felt in the shifter, steering wheel, pedals, etc. Basically you can feel it in the entire car. It ONLY happens while I'm moving. When idling the engine runs smooth. Once I start moving, the vibration starts and continues regardless of what gear I'm in. Once I've driven it for about a quarter mile, the vibration stops pretty abruptly. One second its there, the next second its running just as smooth as it normally would. This leads me to believe there is something going on in the transmission, but I have no idea where to even start looking.

Anybody have any insight here?

 

[541joseph]

Does it change with speed or still do it when the clutch is pushed in?

 

[rhobere]

It looks like my initial assessment was wrong. I paid a little closer attention this morning and it turns out the vibration occurs when idling before the truck is even in gear. It just doesn't become very noticeable until I am in gear, at which point it becomes very noticeable. So its definitely NOT a drivetrain problem.

I'm guessing that answers your question and/or makes it irrelevant, Joseph?

I'm going to start by changing the spark plugs this weekend unless someone has any other suggestions...

Also, if a mod sees this, can you change the thread title to Engine Vibration when Cold? Thanks

 

[junkyardbiker]

Check your compression. I had an old 6.5 diesel that shook like hell until it warmed up and the rings set. It would fail compression when cold but had great compression when warmed up.

 

[rhobere]

bump for update...

I filled up my gas tank Monday night and haven't had the problem since. Is it possible that bad gas could cause vibration when cold? Maybe the fuel pump is having issues at low tank volume? The fuel filter is less than a year old so I don't think there is a problem there.

If it starts acting up again, I'll definitely take it in for a compression test. A bad piston ring was both what I was fearing most, but also the most plausible explanation I could come up with.