2000 3.0 4x4 misfire on cylinder 5 and 6

[firstinfireman]

I have a misfire on number five and six I have changed plugs wires and coil pack. still missing on those two cylinders.

 

[BRUTUS_T_HOG]

try widening the spark plug gap by about 10-15 thousandths, if that doesn't work then check compression, then check fuel injectors

 

[stiluv]

i had the same problem it was a burned valve. it could also be a head gasket check to see if you have water in your oil.

 

[firstinfireman]

well i did go back and check gaps on spark plugs and now they are right. some were off up to 15% it now runs a little better but still only on four cyl. When i unplug the spark plug wires from the coil 4 and 5 make no difference to the idle of the engine. not even when both are unplugged at the same time. The plugs are getting fire though. no water in oil how big a job would it be if it was valves... vaccum leak?

 

[BRUTUS_T_HOG]

start small then work your way up, check to see that the coil for 5 and 6 is being triggered, connect a non powered test light to the positive battery cable, then back probe the ground wire for each coil, if its being triggered and you can confirm it has spark, then check that those injectors are being triggered

if they are both being triggered, i think i already said this, do a compression test

test all cylinders for comparison, they shouldn't vary by more than 10%

if 5 and 6 are low, you might have a blown head gasket

 

[firstinfireman]

I dont know too much about engines wouldnt you be losing water level with a blownhead gasket? I will start there though. When i take off the spark plug wire from those two outlets there is arch between the two if you hold it near . How do you go about checking to see if the injectors are being triggered?... hwere are they

 

[BRUTUS_T_HOG]

same way i just said to check if the coils are being triggered, and if 5 and 6 showed low compression then the head gasket would be blown in between cylinders and no coolant would be near the hole, had this happen MANY times on 1.9l escorts because of there lack of head bolts

 

[Quiksurf]

it may sound stupid, but are the wire on the coil correctly?

 

[firstinfireman]

thanks for the help i have not had a chance to mess with it any more since my last post. I will definately go that route. As for wires in the wrong place on the coil... already thought of that since the order of fire is awkward on the coil 123465 design flaw in my book.