Last year's race winner Ryan Briscoe led the way in the second and final free practice session before qualifying for the Milwaukee round of the IndyCar Series.
The Penske driver, who turned his 2008 season around with victory at the one mile oval twelve months ago, beat Newman/Haas/Lanigan's Graham Rahal by 0.0152 seconds, with Tony Kanaan third for Andretti Green Racing.
All three were part of the first group to run in the split session, with Ganassi's Scott Dixon the best from group two in fourth overall, ahead of team-mate Dario Franchitti.
Mario Moraes continued to show strong oval pace with sixth for KV Racing, while last week's Indianapolis 500 winner Helio Castroneves was eighth in Penske's second car, behind Danica Patrick (AGR).
Raphael Matos was top rookie this time in ninth for Luczo Dragon Racing, just ahead of fellow newcomers Robert Doornbos (NHLR) and Mike Conway (Dreyer & Reinbold).
Paul Tracy struggled with understeer on his first day as a AJ Foyt Enterprises driver and was only 18th, while Panther's Dan Wheldon - who had lost most of first practice to a steering rack issue - was slowest of all and nearly two seconds off the pace.
Stanton Barrett has withdrawn from the meeting after heavily damaging his 3G car early in morning practice. His departure brings the field down to 20 entries as Conquest Racing is also skipping this event.
Pos Driver Team Time
1. Ryan Briscoe Penske 21.7318s
2. Graham Rahal Newman/Haas/Lanigan 21.7470s + 0.0152s
3. Tony Kanaan Andretti Green 21.9279s + 0.1961s
4. Scott Dixon Ganassi 21.9435s + 0.2117s
5. Dario Franchitti Ganassi 22.0206s + 0.2888s
6. Mario Moraes KV 22.1076s + 0.3758s
7. Danica Patrick Andretti Green 22.1540s + 0.4222s
8. Helio Castroneves Penske 22.2096s + 0.4778s
9. Raphael Matos Luczo Dragon 22.3095s + 0.5777s
10. Robert Doornbos Newman/Haas/Lanigan 22.3709s + 0.6391s
11. Mike Conway Dreyer & Reinbold 22.5649s + 0.8331s
12. Hideki Mutoh Andretti Green 22.5894s + 0.8576s
13. EJ Viso HVM 22.7124s + 0.9806s
14. Tomas Scheckter Dreyer & Reinbold 22.7763s + 1.0445s
15. Ryan Hunter-Reay Vision 22.8034s + 1.0716s
16. Justin Wilson Coyne 22.8132s + 1.0814s
17. Marco Andretti Andretti Green 22.8726s + 1.1408s
18. Paul Tracy Foyt 22.9209s + 1.1891s
19. Ed Carpenter Vision 23.4762s + 1.7444s
20. Dan Wheldon Panther 23.6632s + 1.9314s