A little more info... I pulled the plugs for cyl's 4 & 5 and grounded them against the exhaust header and started the engine and they both have a fairly fat, blue spark. I plugged in my compression tester and checked both cylinders and they both read 120 psi. It seems the only thing left is that those two cylinders are not getting fuel, but it seems highly unlikely that two injectors would stop delivering gas at the same time. Can anyone else come up with any alternate scenarios?