2003 E350 Plugs/COP

What's the quickest and easiest way to check and change the plugs and COP? I'm getting misfire upon acceleration. Van has 145K miles

1) Are you getting misfires on a single cylinder, or random misfires on all cylinders?
2) How many miles are on the plugs?

The plugs have about 25K on them. Seems to misfire on accelerating more on hot days and higher altitudes. Occasionally get a "check engine light" but it goes away when driving easy at 55 mph on level ground. I can't tell which cyl or how many. Starts and idles just fine. I would like to pull one plug just to see...Can't see plugs without removing stuff....which plug is the easiest to get to?

Plugs are usually good for 100K miles, and we only replace COP's as needed.
1) Clean air filter
2) Clean MAF/IACT sensors.
3) Replace fuel filter.
4) Check fuel pressure.

Do a Google ''Youtube Auto how to clean a MAF sensor''

How's the fuel economy?
It might be time for new upstream H02 sensors too, if over 100K miles.

Thanks for the detailed info. How do I clean MAF/IACT sensors and where are they.
Should I be able to see a spark arcing if the coil or plug is bad?

The MAF/IACT sensors are in the air duct, it's inbetween the air filter box and the throttle body, look for the electrical connection.

See COP Test, http://www.automotiveforums.com/vbulletin/showthread.php?t=906504

The best price for COP's are probably on www.ebay.com (http://www.ebay.com)