I have an 1993 Dodge Van B150, 3.9 engine. I have noticed misfires when the temp gets cold. It seems to happen after the engine warms up a little and with speeds 35 mph and above.
Have tried dry gas. Before winter I did remove the inside of the catalytic converter. The O2 sensor is before the converter.

Have you replace the spark plugs lately (Champion only)? Use the exact plug that came in the van and gap to spec.

Recently, a 2001 Dodge Ram pickup truck I was working on would not start. The owner had installed Splitfire spark plugs, which worked for a while. Later, they broke down and prevented the truck from starting. Installing the specified Champion plugs solved the problem.

I have an 1993 Dodge Van B150, 3.9 engine. I have noticed misfires when the temp gets cold. It seems to happen after the engine warms up a little and with speeds 35 mph and above.
Have tried dry gas. Before winter I did remove the inside of the catalytic converter. The O2 sensor is before the converter.
I don't know if I'd post on the internet that I deliberately modifed federally mandated emissions components, but it's too late now.

Have replaced the fuel filter? Also, you may have an ignition coil that's beginning to break down. Colder temperatures and higher engine speeds require a good supply of fuel and a strong spark.