I am no expert on the Suburbans ... yet, but I'll speak based on other auto experience. BMWs as an example have a classic symptom with regard to their front suspensions. When the control arms or the bushings are bad, almost like clockwork at 55 MPH the cars (2000+generation) would start to get a shimmy. At around 60 MPH it is gone. I guess it was something like a resonance mechanical frequency created that shimmy at that speed.
What you describe sounds like that since it seems to occur at a pretty specific speed. The fact that the check engine light came on might be purely coincidental. That is unless you can duplicate it multiple times. If so, then it starts to suggest it might be a drive train issue.
You have a '98 which is similar to my '99. So far, from what I am learning the bushings and ball joints on these trucks wear out and can cause vibrations or shimmies while driving, especially as you reach freeway speeds. Certainly do what Pikey stated as that will help narrow things down.
Another thing to consider are your tires and wheels. Do the vibrations continue or increase in oscillations / frequency as the speed increases or does the truck seem to get smoother as you go faster. If the vibrations seem to be more frequent with speed it could be a wheel balancing issue. If the truck seems to get smoother with increased speed then my suspicions will lie with the suspension - especially around the ball joints, control arm bushings, etc.
What you describe sounds like that since it seems to occur at a pretty specific speed. The fact that the check engine light came on might be purely coincidental. That is unless you can duplicate it multiple times. If so, then it starts to suggest it might be a drive train issue.
You have a '98 which is similar to my '99. So far, from what I am learning the bushings and ball joints on these trucks wear out and can cause vibrations or shimmies while driving, especially as you reach freeway speeds. Certainly do what Pikey stated as that will help narrow things down.
Another thing to consider are your tires and wheels. Do the vibrations continue or increase in oscillations / frequency as the speed increases or does the truck seem to get smoother as you go faster. If the vibrations seem to be more frequent with speed it could be a wheel balancing issue. If the truck seems to get smoother with increased speed then my suspicions will lie with the suspension - especially around the ball joints, control arm bushings, etc.
