Chevrolet Repair: truck missing / car does not have good heat, ford f 150, chevrolet caprice

Question
Hi, I have a 1993 ford f-150 2 wheel drive straight six 4.9 liter changed everything I could think of still has a slight miss do you have any idea's?? I also have a 1992 chevrolet caprice 305 a/c and heat work and the blower blows good but does not blow very strong out of vent's heater or defroster any idea's would be appreciated thank you for your time and help??

Answer
Hi Robert... I am not much of a Ford person, but i would look at the ign system for a miss...maybe one wire mixed up in the firing order...on the cap...on the Chev...check to see if anything may have fell down thru the defrost duct and may be jamming the cold air door in the heater box...check for a vacum leak to the heater control...also check the fresh air ducts in front of the windshield under the hood and make sure the are not plugged...basicly one of the doors inside the heater box is stuck open a little or jammed with something so the air flow is is going in two differant directions...hope this helps