Interesting Problem

[ezrider440]

Hi there folks, my problem is as follows my 5.0 explorer has a sudden noise coming from the passenger's side motor compartment, a little history, the short block has a 100k the heads, cam and rotating gear have less than 20k, i had a cross fire on the last two cylinders on the passenger's side, those would probably be 8 and 6, anyhow i changed the wires which cured the cross fire, and i changed my bosch plugs to motorcraft, even though i never had any problems with the bosch plugs but everyone seems to hate them so i gave in, right afterward i have a slight tick on the passenger's side of the motor, now it's not a valve tick, my theory is that it's the exhaust leak which i can hear at hard acceleration but not a tick more of a throaty leak, it's not the EGR because my truck is a 1996 with without the EGR down tube, so my theory is that because it's cold recently the manifold contracts and gives me a leakage since when i am driving there is not sound, or my cat has some gasoline in it from when i was running on 7 cykinders for a day, any ideas? my whole issue is why do i get this noiise right after i changed the plugs? thanks in advance