1998 4.6L.
This may be a dumb question, but that hasn't stopped me before....

Why does my truck not want to run when the air filter is removed?

Thanks!

 

you probably have a vacuum line and / or the air flow sensor removed or unplugged.

 

x2. You must not be talking about removing the filter itself, but the whole filter housing? If that's the case, it is because you've disconnected your Mass Airflow sensor.

There is no reason the truck would not run by simply removing the filter.