Need help figuring it out, have a '98 Exploer, 5.0

[lbrissette17]

When I'm driving, after i get up to about 45-50, it will start shaking back and forth and sounds bad. It will do it but if i give it a bit more gas or less gas it will stop. I used to think it was only when the rpm's were higher around 2000, but it sometimes does it around 1500 or when I'm around 35-50 mph.

 

[Flash]

Try bleeding your power steering first, it's easy and a pretty likely cause.
Air gets into the system if you turn the front wheels with the engine off.

You have to cycle the steering from left to right a few times, do a few figure 8s in a big car park.
It seems an unlikely cause but if you do a search you'll see it comes up a lot.

If it persists try a wheel balance and check for bent wheels and deformed tyres.

 

[Dave 1955]

Thats what was wrong with mine a few years ago...I turned the wheels to do the brakes with the motor off is what caused it.

 

[J_C]

I assume it's shaking from the front? If bleeding the power steering as Flash mentioned doesn't help, you might pull the wheels off and inspect the front suspension as well as checking the wheels/tires.