P0316 Ford - f150 4.6 2006

Question

My ford f150 is an 2006 4.6 v8.It shows a code po316.How do I tell what is the problem? I have changed the coil on #6.It cranks rough and runs rough for about 2 mins.

Answer 1

P0316 Misfire detected on start up

It crank rough? When the engine even worn and you just crank it and the sound is smooth this is a indication of even compression. When it rough and there is a low spot during the cranking and the cranking is not smooth this is a indication of a mecahnical condition.This is what is called a relative compression.do a compression test on the cylinder if there is a 25 % difference there is a problem