I have a 2003 4.2l V6 that can’t drive in cold weather. Anything below 40 degrees. It starts and runs like nothing is wrong. While in park revs normally, but when driving and trying to accelerate the pistons stop firing( doesn’t turn off) as soon as you release the gas pedal everything comes back to life… you can feather the gas and crawl along. In the past year I’ve installed new
crankshaft position sensor
camshaft position sensor
throttle position sensor
mass airflow sensor
upstream 02 sensor (only code it ever displayed)
coil pack and spark plugs
catalytic converters
cylinder Head temp sensor.
PCV valve
fuel filter
alternator/idler pulley/tensioner assembly

 

Welcome! Any codes?

 

No there are no codes shown

 

which happened first, the problem described, or installation of all those parts ?

 

I replaced or had a mechanic replace all of those parts in an effort to fix the problem. It started last winter and as soon as it warmed up a little bit outside it was fine. Drove it all summer with no issues.

 

I have a 2003 f150 4.2 that is doing the exact same thing. did you find out what the cause was? thanks

 

Do you have any Diagnostic Trouble Codes (DTCs)? Autozone or other will read for free.
Make sure the Mass Air Flow sensor (MAF) is plugged in.
What does your instrument cluster temperature gauge read when first started and then after full warmup?
Check and make sure the wire is connected to the cylinder Head Temperature sensor (CHT).

Below I have listed info from RockAuto website for my 2007 ( yours is a 2004) indicating that your may also have an air charge sensor.

FORD > 2007 > F-150 > 4.6L V8 > Engine > Cylinder Head Temperature Sensor STANDARD MOTOR PRODUCTS TX91
FORD > 2007 > F-150 > 4.6L V8 > Fuel & Air > Air Intake / Charge Temperature Sensor STANDARD MOTOR PRODUCTS AX31T