Logan Sargeant earned a second successive FIA Formula 3 pole position at Silverstone, while his championship-leading Prema team-mate Oscar Piastri hit trouble.
Sargeant led Renault junior Piastri after the first qualifying run, but Piastri was forced to stop his car just before the entrance to the pitlane halfway through the session.
As the marshals began to recover his car, Piastri was able to restart the car and he returned to the pits.
The remaining drivers took to the circuit for their second and final qualifying runs, and Australian racer Piastri joined them on the track a few minutes later.
However, Piastri's car then stopped again and brought out the red flags while his rivals were attempting to displace Piastri's team-mate Sargeant from the top of the timesheets.
The stewards noted the incident and confirmed they would investigate one-time FIA F3 race winner Piastri after the session.
Just three drivers were able to set a lap time before the red flag, with Ferrari junior Enzo Fittipaldi (HWA Racelab) improving to third place.
The session restarted with just under four minutes remaining, and Sargeant improved by over half a second to earn his second-straight FIA F3 pole with a 1m45.063s.
Red Bull junior Liam Lawson, who won last Saturday's race from second on the grid, will once again line-up on the front row alongside Sargeant.
HWA Racelab driver Jake Hughes was third-fastest on home soil ahead of Sargeant's Prema team-mate Frederik Vesti and MP Motorsport's Bent Viscaal.
Sauber junior Theo Pourchaire will line-up in sixth place for ART Grand Prix, with Red Bull Junior Jack Doohan in a career-best seventh place on the grid for HWA.
In only his second weekend back racing in single-seaters for the first time since 2016, Ben Barnicoat was an excellent eighth fastest for Carlin behind practice pace-setting Trident driver David Beckmann.
Beckmann's team-mate Lirim Zendeli rounded out the top 10 in the 30-minute session.
Reigning Formula Renault Eurocup champion Piastri had tumbled to 11th place by the end of the session.
Fittipaldi and ART GP duo Alexander Smolyar and Sebastian Fernandez all improved immediately before the red flag caused by Piastri but fell to 13th, 17th and 19th positions respectively.
Silverstone F3 starting grid
|1||Logan Sargeant||Prema Racing||1m45.063s|
|2||Liam Lawson||Hitech GP||0.234s|
|4||Frederik Vesti||Prema Racing||0.521s|
|5||Bent Viscaal||MP Motorsport||0.534s|
|6||Theo Pourchaire||ART Grand Prix||0.567s|
|11||Oscar Piastri||Prema Racing||0.814s|
|14||Matteo Nannini||Jenzer Motorsport||0.909s|
|16||Max Fewtrell||Hitech GP||0.966s|
|17||Alexander Smolyar||ART Grand Prix||0.972s|
|18||Alex Peroni||Campos Racing||1.021s|
|19||Sebastian Fernandez||ART Grand Prix||1.134s|
|20||Calan Williams||Jenzer Motorsport||1.158s|
|21||Federico Malvestiti||Jenzer Motorsport||1.216s|
|24||Dennis Hauger||Hitech GP||1.496s|
|27||Richard Verschoor||MP Motorsport||1.648s|
|28||Lukas Dunner||MP Motorsport||2.075s|
|29||Sophia Florsch||Campos Racing||2.179s|
|30||Alessio Deledda||Campos Racing||2.797s|