O2 sensor questions?

Will an O2 sensor be affected by heat. Now i dont mean the exhaust gas temp i mean cold weather or hot weather. I know sounds like a dumb guestion but i can't tell if its my ignition coil or O2 sensor that is causing the skip. The skip only occurs when the motor is up to temperature and is also affected sometimes by percipitation. It sounds like a cap but the cap is brand new and it isn't just a single cylinder skip it is a whole engine miss fire. The plugs are white which suggests its lean so i am thinking its the O2 sensor but not sure if that would cause the engine to run lean in the mid rpm range or not.

No indication of year.
That will help folks to know what computer you have and how many sensors.

Also, do you have a check engine light, or have you checked for "Codes"?

In general. The output of a O2 sensor is affected by a number of factors, including whether you have an upsteam exhaust leak.

As for ignition: I have had a catostrophic failure of both the rotor and cap. Very odd symptom. It would not run at altitude, but at a lower altitude, it ran fine. Idled great when I shut it off, and would restart at any time. Rotor was a glob of plastic and the cap was a big arc trail. There were no metal contacts on the rotor, and I found them on the bottom of the distributor.
...Just for shits, you might want to look under the cap...

Ron

Yeah i have a cracked manifold, It's a 94 4.0L 5 speed. I need new motor mounts they come in this week till then i can't fix the exhaust leak. If thats the problem why didn't it skip when i first bought it 2 month's ago, it was cracked then. It's wierd it ran better with the melted cap and bent rotor with the factory plugs with 200,000 miles on them then with all the new stuff.

you might want to read through this thread...this guy had a mid range misfire problem also...he fixed his by resetting his distributor timing....

http://www.naxja.org/forum/showthread.php?t=939372