The Kiwi has endured a horror start to the Darwin Triple Crown, effectively getting nothing in the way of useful running from the two Friday practice sessions.
With that rectified for practice 2, van Gisbergen found himself battling both a throttle response issue, and a tracking problem which meant the car was wandering under brakes.
Triple Eight attempted to identify the steering issue during the session but was unsuccessful, the driver out of the car well before the chequered flag came out.
According to Edwards the steering issue is the more concerning of the two, particularly as they can't find anything broken on the car.
"We don't know," he told the Fox Sports broadcast. "We've been struggling with it both practice sessions.
"In the end we're just throwing some things at it just to try some concepts to see if we can narrow it down. But it's not making sense. Under brakes it's pulling, but we can't narrow it down."
The lack of useful running today means van Gisbergen will have his work cut out in qualifying tomorrow, given that's the next on-track session.
"We got nothing; both [practice] sessions were pretty much a write-off," he said.
"You just can't lose that running time. [It is] straight into quali tomorrow.
"We've got no confidence. We'll re-group and have another go, but it's concerning.
"The throttle [response] is not as good as it's been, but that's a seperate thing. We can probably manage that. This is difficult. We can't drive around this. We'll see what we get."
