Truck shakes bad over 60mph?

[Heath Andrews]

1993 5.7 350 auto with 162K on stock motor and an unknown amount on 3rd transmission. Pretty far over 100K though. Maybe roughly 110-140K. Happened back in the mid 90s and pops can't remember the exact mileage.

Anyways, been having this problem for awhile but I'll to take this truck to college (4 hours away) and this needs to get resolved. After I hit speeds anywhere above 60 mph be it cruise control or not, the thing will randomly start shaking pretty violently. It's almost as if it's trying to shift but can can't lock in a gear. I have to either mash the throttle to drop a gear or let off the gas to slow down and stop whatever its trying to do. It won't resolve the shake on its own I have to do one or the other. Whenever it's gets up

 

[Heath Andrews]

Check your spark plugs, wires, cap and rotor,
Your starter solenoid and your grounds. One truck did that with cracked plugs one the starter, then two months later a ground came loose

 

[1500z71]

Check your spark plugs, wires, cap and rotor,
Your starter solenoid and your grounds. One truck did that with cracked plugs one the starter, then two months later a ground came loose

This is kind of an update as I haven't had time to take it to my buddy but he thinks it's in need of a tune-up in regards to what you just mentioned. He said he remembers it doing it to him in the past whenever he's had it. This week I can get it to him and hopefully one of the easy above will be the issue.

 

[magimerlin]

If you don't know when the last tune up was and the consensus is it may need one........ just do it.. it ain't hard to do and it's not expensive. Cap, rotor, plugs, wires, air filter, fuel filter, done....

sent from what use to be a great country...

 

[magimerlin]

Did you ever get the tires checked out?

sent from what use to be a great country...

 

[1500z71]

Did you ever get the tires checked out?

sent from what use to be a great country...

No sir haven't had the time to yet. I'm going to do the tune up first though since it's very likely in need of one and hopefully that will solve the problem.

 

[1500z71]

The tune-up did not work. I actually decided to take a video this time. You can hear the steering column and can see the hood shaking. The click at the end is me turning the cruise control off (like letting off the gas). The sound of the truck in the video is night and day.

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[Heath Andrews]

Are your motor/Transmisson mounts in good shape? How's the catalytic converter?

 

[1500z71]

Are your motor/Transmisson mounts in good shape? How's the catalytic converter?

I haven't checked the mounts and I'm not running cats. I tell ya I had it serviced new plugs and wires and it seemed to help a good amount but the problem still exists.

 

[ChristGilley]

I had a similar problem with my 81 and the problem was a separation in the tire. Might mot be your problem but definitely worth a look. The truck would shake so bad I thought the front end would come out from under it


Sent while pulling out a Ford