WOT can read anywhere from 4.5 to 5.1 max it all depends on the setting. Push the throttle blade all the way open by hand and see what it reads. If it doesn't open that far by pushing the gas pedal, you've got some slop somewhere in the linkage.

Setting your timing at 17 is pushing it. The timing tables and any adders or multipliers are set up assuming a base timing of 10 degrees. If you set it at 17 degrees. the computer is commanding a timing of 7 degrees higher than it thinks it is everywhere...including at WOT. For example, the stock A9P EEC is commanding 26 degrees of timing at WOT at 5500 rshared_pm and above, including that 10 degree base. So, total is 26 degrees. If, however, you set your base at 17 degrees, your timing at WOT and 5500 rshared_pm and above is going to be 33degrees. That can get you into trouble, especially if you are boosting or on the juice.