My truck shakes when i'm backing out or moving slowly. what could it be?

Try slowly moving the vehicle in reverse and trying to shift back to 2 wd.....do not force.....shift fork damage could occur.....Try slowly moving the vehicle forward as well....Move the shifter firmly but don't force it.......Make sure the hub locks are in the free position too...........

Need to check each wheel at a time, for running true ie:- buckled wheel, loose wheel nuts, tyre faults warped tread, bulges. Then check transmission, wheel bearings, prop shaft universal joints, gearbox and engine mountings.

Sounds like the engine is starving for fuel. You might try changing the fuel filter. It also cold be water in your fuel tank. Try putting some dry gas in the tank.

check ur axle or half shaft it goes from the transmission to the wheel if they break it wont go anywhere it has rubber boots on each end of yhe shaft with universals in them

If the sensor is in the dist, the dist shaft could be worn and slowly damaging the new sensor.
Could also be a new problem.

You need to find out what the code is that is causing the check engine light. Have you verified that the spark plug wires are in the correct order?

it sounds like the front tires need balancing.if you drive the truck slowly(creeping down the road at about 5mph)and lightly holding the steering wheel do you feel the steering wheel moving back and forth.this could indicate a bad belt in a tire where as a wheel imbalance won`t show up at this low of a speed,but a bad belt will.also have the front end checked for worn front end components and wheel bearings,this can cause a bad shake too.

Does it gallop when you are sitting idle and the RMP gauge bounce up and down between 1000 and 1500? If so, clean the throttle body and see if that solves the problem. I had a similar problem with my 03 Yukon XL (same truck) and cleaning the throttle body fixed it.

check your engine mounts

Some things you can check. 1 jack up one side at a time. Grasp the tire on each side and try to move the tire, if you can move it you have a bad inner tie rod on that side. You can also grasp the tire at the top and bottom and try to move it that way as well, this will tell you if you have bad ball joints. I suspect a bad inner tie rod here as you have replaced everything else. If you check both front tires and nothing is loose your problem lies in your front brake rotors. Hope this gives you some help and thank you for using FixYa!

Sincerely,

JC