i have a po303 code on a 2003 ranger 3,0l i just replaced motor with a crate motor .

Question

the engine is brandnew ,factory crate motor all acessorys ,sensors,any external electrical,from the firewall to motor been replaced new,including fuel lines,pump,cats. as soon as i fired it up instantly threw po303 and running ruff  im out of options unless its the pcm,ecu,ect,ect,ect should that be next?

Answer 1

P0303 Misfire number 3 cylinder

​ The ignition coil, these are popular for setting a misfire condition, the best way to test these is is to use a ignition analyzer , even if there is spark its the quality of the spark, a sharp crisp blue in color not reddish,