[stew57]

This one has me scratching my head, but then again I do that a lot when it comes to truck repairs. I have a 98 Suburban K1500 5.7 4x4 and over the last few days something has started to happen.
When I hit speeds of 60 and again at 65 the truck vibrates in the front end, and only at those speeds. It also made the service engine light come on yesterday but not today, still had the vibrations at those speeds.
Well never had this happen before, I can build a great home and build a great set of golf clubs but when it comes to trucks I'm lost. Now I can tell you what's wrong and follow directions, so my eyes are open and I'm ready.
I thank you guy's that know these type of things and it's so great to have sites like this for us shade tree mechanic's. Hope to read ton's of input and I really pray that the problem is not major.
Thanks,
Jerry
God Bless

 

[Pikey]

Is the light flashing? We need to try to narrow down if it is the engine, suspension, or drive train. If you put your foot on the brake and give it had will it vibrate? Jack up the front end and spin the tires by hand. Feel any crunchiness? Grab the tire at 9 and 3 o'clock, give it a wiggle any movement? Do the same at 12 and 6 o'clock. It could be a bad wheel hub, thrown wheel weight, bad cv shaft ( if 4x4), bad ujoints. That is why we need to try to narrow it down. Have that code read at a parts store and tell us what it is. That could help also

 

[stew57]

The engine light came on the first day but yesterday, I have not driven it today but will later and if light comes on I'll stop at a Auto Store to check the computer. I will check those things you ask for this coming weekend and post my findings, if I get any codes I'll post those same day. Pikey what did you mean when asking about putting my foot on the brakes? Thanks for the input and I'll check later to see if you have replied.

 

[Pikey]

It is called a brake torque. You hold your foot on the brake pedal so the truck will not move and press the gas pedal. I am just wondering if your service engine soon light was some sort of misfire detected

 

[Aquila99Sub]

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.

 

[stew57]

Pikey thanks for the reply and I'll try that today, and thanks to all for the input. I have many things to check out this weekend and I'll update to how things went first of the week. Again thanks to all that left input and I pray that it's something simple and non-costly.
Thanks, Jerry
God Bless

 

[BoneHead]

The last few times I've had something like this happen it ended up simply being tires were out of balance. It happens from time to time and depending on where you got the tires from, it should be a simple fix. Although I will admit it was on a 2wd S-10, a couple times on my 85 c10, and my old Malibu. I haven't felt it from the tires on my 4wd yet.

One question though, the vibrations, do you feel it in the steering wheel, or on your feet like it's coming from the floor boards?

 

[poncho62]

Could be wheel/tire balance....could be as simple as ice build up on the wheel if you live in a cold area. Also could be a wheel bearing or loose suspension part.
Dont know why the service light comes on, could just be a coincidence

 

[stew57]

Ok thanks for all the input and at this point it's parked and not moving. Had not driven it since last week when all this started, took it out today and it's sitting at a friends house. Went out to take care a a few things and took the suburban and I noticed it start to clog down, misfire, act as it's not getting fuel. Now this did not happen the whole time I drove just part of the time. Went to friends house and it died while I was parking, tried to crank and it misfired and acted as like there was a fuel issue. When I did get it started it would die when I put it in gear, was able to start it but never got it to drive again. It will not go into gear without dying, so I hope some one has an idea. I plan on spending some time over there tomorrow, plan on removing the plugs and checking them, maybe put a new fuel filter on. So if this has happen to anyone or if someone has an idea of what's wrong please share.
Thanks,
Jerry
God Bless

 

[Pikey]

Check fuel pressure with a gauge.