could cold weather cause a engine computer to fail? And fail only when cold and resume working with warm weather?

I know the CCM is close to an outside wall in the passenger compartment and the engine compartment connector is shielded some what from direct engine heat.

 

It could just be a bad solder joint.

Heat makes things expand and cold makes things contract.

http://www.ehow.com/how_4798949_chec...der-joint.html

 

made it through another summer running great, temp is just now dropping and here comes the miss. Not sure it could be the computer because it is inside the passenger compartment, so it should be warm. The engine heats itself up even in cold weather.

It has to be the air temperature or a sensor that measures air.

any new ideas?

 

Not to deviate from your subject but might change you fuel filter if it hasn't been changed in a while. Could have picked up some water in the fuel. not uncommon. Also check out your fuel pump drive control module by the spare tire notorious for corroding out and exposing the circuit board. you have to take it off and check out the back side. the new one comes with spacers to space it away from the cross member.

It controls fuel pump speed therefore controlling fuel pressure.

 

I have thought of items like this before (filter is new). The miss is only there at idle, not after you engage throttle. Since all soft hoses are new and hard lines have been vacuum tested, I feel it is some type of valve that operates part of the time at idle only.

I have pulled up to a stop light and have it idle fine for a few seconds then boom, rough just like someone pulled a hose. Then it's foot on gas and foot on brake till the green light.

 

A 2001 F150 does not have a FPDM.

OP - time for some comprehensive diags for the sensors; there aren't that many that 'track' with ambient/engine temps - IAT, MAF, ECT/CHT.

Anything else - yer just guessing.

There are methods to check each yerself with a DMM - you need the transfer tables for each to do this.

MGD

 

What is a 'DMM', I would love something else to try on it

 

http://en.wikipedia.org/wiki/Multimeter

 

Digital multimeter.

Some tests require the ohm function, others the voltmeter function.

You need the tables ( or graphs ) that relate resistance/voltage to temperature. The MAF is more complicated ...

Anyway - this is an example of what a DIY'er can do: http://www.f150forum.com/f6/egr-evap...66/?styleid=14

MGD

 

While this issue only happens in cold weather, it had times when it is cold and it does not happen. For example, stop at light and idle perfect then all at once crappy idle.

It has to be either a sensor reading wrong or some smog valve opening when it is not supposed to. There are some valves on the firewall next to the brake booster. Anybody know what they do?