I need to take my truck in for emissions testing, I fixed the problem, should I clear the code?

Clear the KAM (Keep Alive Memory) by disconnecting the battery for 10 minutes, this is necessary on a Ford PCM (Powertrain Control Module) because, a lot of times the EVAP system Component Monitor will not run if the KAM is not reset, after clearing the KAM, hook up your code reader and be sure the code # P1000 is stored, this will initiate the running of the Component Monitors.

NOTE: After performing the KAM reset, it will be necessary to allow the vehicle to sit for 5-6 hours because the EVAP monitor will only run from a "cold start"

Also, you did not mention what state you are in but VA. requires all but 2 monitors have to be "Ready"

If you cleared the code, you have to drive the truck around for a while to reset the I/M monitors, or else it still might not pass the emissions test even with the MIL off.

I would clear the code, but it won't matter much for passing the emissions testing. The system will show that codes have recently been cleared for as long as it would take to clear on its own. The benefit of clearing the codes is that any code masked by the current code will appear sooner.

If you have the scanner, clear the code. It will confirm if you have located the source of the problem. Some vehicles will clear indicators themselves if a predetermined number of "clean starts" are recorded.