ok guys and gals this truck of my bosses has two cats the one from factory where to two pipes go in and a single goes out then there is another cat and a glass pack the truck when it was running was real quiet like a new truck, why would there be two and if they get stopped up would it kill the truck from running right, why i ask this a month in a half ago the truck just died and i had to have it towed home well it acted like it jumped time so i replaces the timing chain have everything dead on correct well it started and missed and cut off, would not start back then it started back missing again, would smooth out at high rpms then go dead now it misses through out the rpm range, now i have changed
plugs (twice)
wires
caps
rotor
clean iac and test
ing mod on dist tested good
found no vacuum leak
getting gas

OH now i have a craked exhaust manifold now too,

and this is a 302 1987 f 150 2wd auto

i need some help here i have no clue what it can be,
i know if it was my truck i would chunk the fuel injected put on a carb and intake and take that dis. out and put in a points dist. and call it a day after i changed the manifolds to headers and run free flowing exhaust.

 

And in doing that you would probably replace the part that is most likely causing you problems.. the ignition pickup in the distributor or the ingition module(TFI). You would know for sure if this is the problem if you pulled the codes.

The motor needs that anyway so get right on it after you fix the above problem.