What can I do to fix this problem on 1999 Ford Expedition

Got a PO353, PO356,PO358 after changing all Spark Plugs and all Coil on Plugs, also getting misfire when gas pedal is released Starts up fine Checked connects look okay Checked spark plugs look okay Checked wiring

by in El Paso, TX on April 04, 2013
1 answer 1 comment
ANSWER by , April 04, 2013
rec. fuel system clean. ethanol treatment to 1 tank premium fuel. get fuel running through clean to eliminate fouled injectors as possibility.
COMMENT by , April 04, 2013
I also cleaned tank and lines, also new injectors,new EGR Valve, Trottle position sensor, EGR Position sensor, ICV what else can be done