Bourdais finishes Portland test on top

The Frenchman, who had comfortably topped the times on the opening day of work, was again the fastest of the eight drivers on track, which stayed dry for most of the session despite some dark skies threatened rain.

"We've had quite a bit of different weather conditions making things more complicated than they needed to be," said Bourdais.

"The McDonald's car is good and we are just trying to find some improvements and go through the items we had on the list. Hopefully we can get some valuable information and just build for the race weekend."

The Newman/Haas/Lanigan driver finished less than two tenths of a second ahead of teammate Graham Rahal, who held the fastest time of the day for most of the session.

"It's been interesting with the weather, difficult even, but today things have been going well," said Rahal. "I think we're perfectly fine, the car feels really good and when we come back here in a few weeks, we'll be right up front."

Briton Dan Clarke posted the third quickest time for Minardi Team USA, ahead of PKV's Neel Jani and Briton Justin Wilson, who finally took to the track after skipping yesterday's session due to the poor weather conditions.

"The rain was a bit tricky, we wanted to run yesterday and do two days, but it forced us to just one day of running," said Wilson. "It has put us behind a little bit but hopefully we can come back from that."