My buddy has a 98/99 Ford F150 with the 4.2 V6 in it. It was misfiring and rough idling like a **** so we switched plugs and wires ran great. Starter went out this weekend, swaped that out now there is a misfire/rough idle while in drive and a stop. I am confuzored as to what it is. I know both 02 sensors are shot, but would that effect drivability that much?

any ideas what to look at?

 

Could be the head gasket, if the coolant is low, that should be the tell tale sign. The 4.2 98 and older is natorious for the head gasket falling at the #1 cylinder I believe. Cylineder can fill with coolant and bends/ detroy's the rod. If your is going bad, misfire might be caused by coolant in the cylinder. Coolant doesn't burn as well as gas does. I used to have a 99 F-150 with the 4.2 and you can find all kinds of stuff about the head gasket problem on the net. I also believe that there was a volentary recall to replace the head for 98 and older.

 

Found the problem for you.... even circled it.

 

like i said its not mine and i think ford needs to do a bit better engineering of different things after working on this truck

 

Could be bad gas filler up and put some fuel conditioner in it.
Either that or bad plug wires.They will give you problems when its damp out.

Reread your post,Disconnect an O2 sensor to put the truck into a closed loop program
if the problem goes away then you know its a sensor some where.

 

i believe that they had problems with coils and plug to head problems, They also circled the problem allready FORD

 

Very nice