That could be a few things, honestly most of that is the servo not having the muscle to turn the front wheels, I have heard of people moving the steering linkage to the outer most hole on the steering servo horn and then turning down the EPA (end-point adjustment) on the radio, that might help a little but I don't see how that alone would solve the issue. Just make sure your servo isn't trying to push after the wheel binds one way or the other or you could burn out your servo, the other thing is the servo saver could be too loose but that didn't make much difference for me.

I find that on thick grass like when stopped it covers half my wheels, that the steering servo just can't keep the wheels turned in the direction I'm trying to turn, so it'll make HUGE radius turns. But on asphalt, gravel, rocks, or dirt of any kind it works great, no complaints at all. For thick brush/grass I'd say you would probably need a stronger servo (or dual servo's like TRD)

Good luck!