The Dane qualified 19th for this weekend’s Hungarian Grand Prix while team-mate Nico Hulkenberg continued his strong one-lap form by running to 10th place in Budapest.
Magnussen blamed a 0.511s gap in Q1, when both cars were running with hard tyres under the experimental Alternative Tyre Allocation, on his discomfort aboard the VF-23.
He says that as the car has evolved, he has struggled to find consistency in low-fuel and new-tyre conditions as the handling has moved away from his natural driving style.
“[I’m] struggling to find consistency with this year's car,” said Magnussen. “For some reason, I'm struggling a bit on low fuel, new tyres to extract the maximum out of the car.
“Lots of inconsistency for me and as you've seen in FP3, I had purple sector one and then I'm the slowest on sector two, so going very extreme there.
“It's almost like my usual strength have become my weakness in this car.”
Magnussen added that he was content with his long-run pace. However, this has been a particular weakness of Haas this season owing to its struggles to understand and manage tyre wear over a race stint.
Source: Autosport