hi. I have had a little problem recently with my 2000 z71. when i place it in the 4 low gear the engine stumbles and stutters like it had a lack of gas. it only does it in this gear . is this normal ? I use my truck mainly as a tow vehicle for my toy hauler to get in and out of the sand . am i using the wrong gear or what? please any tips or cures for my problem would be appreciated.:confused :