Strange vibration...

[littleblazer]

Hey guys, got a quick question. The truck seems to be developing some strange behavior in the last few days. Basically what's happening is it runs fine. But if I beat on it a little, say rev up to 4k to merge or whatever then shortly after come to a stop, I have a strange vibration. It feels almost like a misfire but not quite as I can still tell all cylinders are firing. The best way to describe it is like if you have the choke on on a carburetor. That surging rough feeling. Idle is stable at 650, in and out of gear doesn't seem to change how it feels. I don't have my scanners with me at the moment to check data either so just looking for input...

Any thoughts? I'm half thinking coil but it wouldn't be random like that... maybe a vvt problem? Plugs are due as is the rest of the 200k service so I know that needs to be done.

 

[HARDTRAILZ]

Clean the throttle body

 

[littleblazer]

I may do that at lunch tbh

 

[mrrsm]

If nothing else remedies the problem... Check the Motor Mounts from below for signs of collapsing and leaking Gel from inside onto the Inner fender Wells. The sudden acceleration will counter-rotate the Engine Block towards the Passenger Side... and if they have gone bad... what is left of the Rubber Carcass casings can shift around in this manner and unsettle how the Engine sits on the Cast Iron Brackets... and the Engine can vibrate and shake like a Chihuahua Sh*tting a Peach Pit when the RPM levels return to near idle.

 

[HARDTRAILZ]

Idle is stable at 650, in and out of gear doesn't seem to change how it feels.

If nothing else remedies the problem... Check the Motor Mounts from below for signs of collapsing and leaking Gel from inside onto the Inner fender Wells. The sudden acceleration will counter-rotate the Engine Block towards the Passenger Side... and if they have gone bad... what is left of the Rubber Carcass casings can shift around in this manner and unsettle how the Engine sits on the Cast Iron Brackets... and the Engine can vibrate and shake like a Chihuahua Sh*tting a Peach Pit when the RPM levels return to near idle.

The mention of no change in or out of gear is why I dismissed the motor mounts as the culprit. Out of gear they are very obvious on this platform.

 

[littleblazer]

If nothing else remedies the problem... Check the Motor Mounts from below for signs of collapsing and leaking Gel from inside onto the Inner fender Wells. The sudden acceleration will counter-rotate the Engine Block towards the Passenger Side... and if they have gone bad... what is left of the Rubber Carcass casings can shift around in this manner and unsettle how the Engine sits on the Cast Iron Brackets... and the Engine can vibrate and shake like a Chihuahua Sh*tting a Peach Pit when the RPM levels return to near idle.

I'd hope it isn't the mounts, the delcos I just put in hardly have 30k on them.

 

[littleblazer]

Also, it's a slower vibration than mounts are...

 

[HARDTRAILZ]

10 htz i think is the mount vibe iirc.

 

[littleblazer]

10 htz i think is the mount vibe iirc.

You can hear that one too though. I can only feel this one. And the motor mounts almost went away after the truck warmed up too. Idk, we shall see what happens.