my f150 with 4.2 v6 misfires and runs rough when first started in the am. after it warms up it runs like new. this truck has 193K miles and runs great other than this problem. any advice. thanks

 

My 4.2 does the same thing. I can't seem to find the problem.

 

I would look into the coil packs plugs wires fuel filter them kinds of things

 

I wouldn't think it would be coil packs or plugs bc it runs fine after a minute. I've changed my air filter and fuel filter already and no difference.

 

have new plugs, wires, O2 sensor's are gettin put on now at shop. hope itll do the trick

 

You are most likely going to find that you have a drippy injector(s) which is coating 1 or more of the plugs with fuel. This causes a misfire until the excess fuel is burnt off. Usually within a matter of a few seconds to possibly a minute or so. It all depends on how bad the drip is. That is where I would check first.

Before starting it one day, pull the plugs and see if any are wet. If so, that is the injector I would see about changing out. With as many miles as you have, on most likely original injectors, the probability of it being the injector is high. One good thing about these, most are interchangeable, so finding a good used one, or set, shouldn't be any big deal. I bought a full set of take out injectors for an 08 GT Mustang for only 10 bucks plus 9.00 freight. They had 7k miles on them. I put them in my 4.6 truck, and it runs like a top now. Before, it had the same slight miss at startup that you are describing. Good luck

 

I'd agree, but since it goes away almost immediately, a coil pack or wires wouldn't cause this description. These would cause an continuous misfire, or more than an occasional bucking of the motor. His clears up completely, so, it either is computer related (sensor) or an fuel injector. The only sensors would be IAC motor, EGR sensor, or temp sensor that could cause these symptoms. I'd go for sure with checking the fuel injectors.

 

I would bet it has nothing to with the ignition system.
My guess without actually seeing the truck would be engine sensor or computer. The truck sounds like it is not getting enough gas when cold so it is running like crap when cold.