Vibration on start

So I am definitely not a car guy. My wife drives our 2004 Jeep Grand Cherokee special edition, 150K miles or so. Recently, it has begun to shake or vibrate after it’s started. The shaking goes away after you drive it a block or two and it doesn’t happen every time. At the moment, there’s no check engine light on. My wife is 7 months pregnant and has always been a bit more high strung about her cars, and every noise, groan, clunk or rattle she gets concerned about if the car is safe to drive.
Anyone have any ideas what may be wrong, if it’s safe, and whether or not it’s a big expensive fix or if I just need to bite the bullet and start looking at a new vehicle?

It sounds like it might be either misfiring or the idle speed is too low. Bring the routine engine maintenance up to date per the owner’s manual, and check the idle air control function. Buying a new car would work too.

Don’t know what engine you have but if is the 5.7 Hemi , you have spark plug wires (16) of them and the same number of plugs. Any crack in the outside of a plug wire that can let moisture in and cause a misfire that goes away as the engine warms.

1 Like

Thanks. It’s a V6, not the hemi.

Sounds like it’s still safe to drive then? Any idea how pricey of a fix it may be?