1999 F-150

[TonkaBass]

I was towing my boat this weekend and my truck had a really bad shake going 55 mph at 1500 rpms. When I went 55mph at higher rmps it didn't shake though. Maybe I just need a new truck! What do you think the problem could be.

[croixflats]

could be U joints or front suspention problems like tie rods or unballanced tire

[Shack]

Was the shake like a wash board shudder you felt in floor boards, or was it the whole truck shaking?

Does it do it when you are not pulling trailer?

When was the last time you had the trans flushed?

[TonkaBass]

The shake is happening when not towing my boat too, just not as severe. The truck shakes and the steering wheel really shakes. I had an allinment not too lang ago and my front end is less than a year old. I am probably due for a tranny flush. I guess I am hoping that it is the tires since they need replacing and I will be getting new ones very soon. 17" rims are expensive for tires though.

[Shack]

By what you just said, I would suspect tires then. The shop you have the tires replaced at will inspect the front end most likely also.

I thought at first of a possible trans/torque converter shudder, but now to me it now sounds like tires. Always a good idea to get the trans flushed if it is over due.

Good luck!

[fishing tech]

With the shake changing with rpm and not speed I would say engine miss or trany. 1500rpm you should be in overdrive which means if it is an engine missit would really shake.

Are you due for a tune up? You may have a coil breaking down.

What engine? What mileage?

[Scott K]

If it is a load shake, rather then a speed shake then most likely a missfire. When it is shaking take it out of OD and see if it still shakes, if it does then you most likely have a tire concern. If it goes away then it is either a enging miss or a trans concern, most likely engine miss. The 5.4 engines were comon for bad coil packs, and the 4.6 were comon for plug wires.

[Shack]

Yep, I did forget about the C.O.P. miss fire shake.

Does the check eng. light come on at all?

Quote:

and the steering wheel really shakes.

I still stand behind tires though, after he said the above.

You never know?

[Scott K]

Maybe both!

[Shack]

Maybe both!

You are right 4.W.E...

Enter the realm of multiple concerns

[Jeremy airjer W]

If it is a load shake, rather then a speed shake then most likely a missfire. When it is shaking take it out of OD and see if it still shakes, if it does then you most likely have a tire concern. If it goes away then it is either a engine miss or a trans concern, most likely engine miss. The 5.4 engines were common for bad coil packs, and the 4.6 were common for plug wires.

I would like to hear the results off doing this!

[dakotakid31]

Have the same year truck and had the same problem. I got the scanner from the auto parts store and it was the #5 misfiring-new coil pack and she was good to go.