On a few occasions....ALWAYS while waiting in the drive thru at the local Whataburger...my truck has started shaking while it sat there idling. It almost feels like a bad motor mount, but I would think if that were the problem then it would ALWAYS do it while idling. It has only done it a few times though and it has only done it at that one place (nothing special about that place). If it does it, I can drive it a bit and then stop and it won't be doing it any more.

Anyone have any idea what might cause it?

 

Maybe your concrete bedliner is out of balance?

 

Hmmm, matbe your truck just doesn't have an appetite for Whataburger bio! I had one of those while in Tx a while back and my body shudders just recalling it

 

Air conditioning will cause this as will the engine fan turning on if you are just sitting.

 

Hoss,
Your truck is trying to keep you healthy? Don't stop at 'WhatABurger'

 

I suppose it COULD be a fan, but I would think it would have done that since day one if that were the case. It just started doing this recently...and it has only done it two or three times. Aside from that, I have literally let it idle for hours during the summer with the A/C running and it never did it then. Only recently...and only at the Whataburger drive through.

What it FEELS like is a bad motor mount, but I would think if that were the case then it would be doing it ANY time it was idling.

 

Hoss,
'WhatABurger' aside, I would have to guess a dirty injector.

 

A little fuel conditioner may be needed.....then run the hell out of it

 

Check out your engine for a injector that is leaking-by , could be a disaster waiting to happen.Do the math on 750 rpm's divided by 60 then divided by 6 for firings per sec and see if that is the originator frequency thats close to what you are feeling.Not trying to sound like an egghead , but would hate to hear of a piston with a hole burned thru the top..................

 

Hoss,
How many miles are on your truck?
Have you changed out your fuel filter lately?
You might have a small amount of water in the system.
All this injector talk is really making things alot worse that it is...
most of the injector related issues seam to be with the 04-04.5 units. Mine has 30k on it and everyhthing has been OK with mine.

 

Is the drive thru on a hill? Mine seems to idle different on hills. Mabye binding or starving for fuel?

 

I am with sawboywv1.....I think it has to do with your Concrete bedliner also.

 

maybe your suspension accidentally flexed like it wasnt supposed to, and screwed the concrete up

 

You forgot to divide by 2 since these engines are 4-strokes

 

It has almost 37K miles on it. The fuel filter was changed at 30K miles.

I don't think it is an injector. It has only done it about 4 times over the past four weeks and only for the 2-3 minutes I sat in line in the morning to get a taquito. If it were an injector I would THINK it would be doing it consistently.

Just the same, I'll run some Diesel Kleen through my next few tanks and see if that makes a difference.