2005 SCREW
5.4 lariat 4x4

Guys and Gals,

Whenever I am cruising along between 40-45mph and let off the gas and then reapply the throttle a hair, I result in a shudder. To make it go away, I have to let completely off the throttle then reapply with enough throttle pressure to get the tranny to downshift.

There is no check engine light on, but will get codes shortly. When the vehicle is in park, there is zero play in the driveshaft but when I place the truck in neutral there is about 1/4" a play (same scenario happened a few yrs ago on my 93 bronco and that was the culprit except it had play when in park).

It doesn't feel like a misfire, but I'm not going to rule anything out.

I'm thinking it could be:
Torque Converter (but would assume it would throw a code)
DriveShaft/u-joint (nothing leaking from the rear pumpkin)

Need some professional opinions. I'm big on not spending $$$ on something I can fix. Thanks everyone in advance for help!!

Stephen

 

Look at my post on that I had the same problem. I took my throttle body off and it was so gunked up it was sticking and hasn't happened since.. Could be something else not sure but there a lot of different suggestions on my post

 

Thanks for the help. Any chance you can post a link from your thread?

 

how many miles are on your truck?
this can happen when you get a bad COP. as soon as the tranny goes into OD, the bad COP wont work, and then you are getting a misfire. it can make you feel like your on a rodeo bull!

of course, there may be another problem, but i know that this one is fairly common. the last time it happened to me, i didnt have a code either.

if you dont want to take it into the shop for a diagnosis, some guys will buy a COP, and just try it one cylinder at a time. in my 99, there was a heater core hose fitting directly above the rear passenger side COP, and when that fitting leaked a little, it shorted out the COP. I would look at your engine, and if you have any hose fittings above a particular COP, i would remove that one first and look near the plug. if it has any water/moisture in there, it is likely your culprit.

good luck!

 

As stated: bad plugs/cops.

Try this; drive around with OD off. This should stop the shudder because you're already down a gear. Not a solution; but it will help you troubleshoot. Also, floor the crap out of it; all the time. This should cause it to misfire enough to actually throw a misfire code so you can figure out which cylinder(s) it is.

Don't do both at the same time.

For one week drive around with OD off. The truck shoudn't buck anywhere near what you're used to. If that's the case? Change your plugs.

Once that's done it should be a night and day difference.

Now if you start to get the same slight hesitation after the plugs have been changed; floor the **** out of it. I mean all the time. This should get it to throw a misfire code so you know which cop(s) to change; unless you just wanna change all of them.

 

Had that happen to a few that I fixed where it was the parking brake shoes sticking due to the hold down pins causing the truck to shutter at 40mph

 

Thanks for the help. Ill start with the COP and let you know what i find.

 

If it is a misfire, which most of you seem pretty certain, would the computer store the misfire codes without actually turning on the CEL?

 

Yes, it should. But, a generic code reader probably won't tell you which cylinder. It would take the dealers computer to say for sure.