Simon Pagenaud has ended final practice fastest ahead of the Iowa Corn 300, with Chevrolet power once again dominating at the sharp end of the order around the Iowa Speedway.
The reigning champion was closely followed by Ed Carpenter, with the team owner enjoying a thoroughly productive day after ending each session within the top four.
Pole sitter Will Power was P3 for Penske, as the attention of the teams and drivers turned to race simulations during the final 30 minutes of track action before the 300-lap race on Sunday.
Championship leader Scott Dixon was fourth for Chip Ganassi Racing, with the four-time champion finally finding some pace after a rather lacklustre start to the weekend.
During practice one and the all-important qualifying session Dixon was unable to even break into the top ten, eventually qualifying a lowly P17 for the race.
Josef Newgarden was P5 for Penske, with the Barber race winner also enduring a tough qualifying session in P16, despite ending the first practice session fastest overall.
Tony Kanaan and Graham Rahal were sixth and seventh respectively, with many drivers running in close proximity of each other in a bid to simulate racing conditions around the tricky short oval.
Helio Castroneves was P8 for Penske, with rumours circulating within the paddock that this may well be the Brazilian veteran’s final IndyCar season.
Mikhail Aleshin and Alexander Rossi rounded out the top ten, in a session which ran incident-free despite a short caution delay for a track inspection.
Esteban Gutierrez ended proceedings P14 for Dale Coyne Racing, just ahead of team-mate Ed Jones as the former Formula 1 racer continues to acclimatise to oval racing.
Further down the order Ryan Hunter-Reay was a disappointing P16, with the three-time Iowa race winner unable to find any pace behind the wheel of his Andretti Autosport machine.
Meanwhile Carlos Munoz managed to return to the track after his minor incident during qualifying, with the Columbian racer ending the session P17 for A.J. Foyt Racing.