An Accord I am looking at has a hard start with full tank , problem. I have been told could be a canister vent purge problem? What have you guys encountered with this symptom, problem wise? That stuff gets expensive fast.

 

If it is a 99 and it's an EVAP problem it should chuck a code.
If the EVAP system is not properly venting, then you may try removing the gas cap and seeing if that relieves the starting issue, if so you know it is a tank pressure problem.

 

If the cap is removed, engine running, the engine will die.

 

Not an expert on Honda's but Try putting the pedal to the floor when you're starting it with a full tank, if its an evap issue it should fire up. If a purge valve goes bad it can let lots of fuel into the intake when you fill the tank, effectively flooding the car, holding the throttle open is an old trick to clear it that most people associate with carbureted cars, but it works with fuel injection as well, they just dont flood as easily. My girlfriends saturn has this problem and we just ingore it, everything works fine and it doesnt throw a code, just gotta know how to get it yo start.

 

Need to check your EVAP system is functioning properly.
Most EVAP codes require a 'two trip' minimum to set the code, and even then it requires certain ambient changes to trip a code. Fresh fuel and half a tank usually are what need to be done to try and chase down a code.