'02 Olds Silhoette Van Small Evap Leak Setting Check Engine Light, Fuel Cap is not the problem

I am wondering if these GM minivans have a common failure point for a small evaporative control leak detected. I've tried two brand new fuel caps, first a Stant and then a Genuine AC-Delco. When I clear the code
it goes away for a short while, but comes back within five or so driving cycles.
I have a code reader, but I don't have one of those nifty smoke machine leak detector set ups. Is there a common failure point which usually is the source of these leaks?
Also, this started happening right after a local dealer butchered the car while replacing the A/C condensor. For example, the two screw type band clamps on the air duct work from the air cleaner to the intake were loose. The also didn't bother to put the caps back onto the A/C pressure test ports. Luckily the caps were still sitting on the cowl so I could clean them off and re-install. They also left the coolant level low and didn't bother to reconnect the various clips which dress off the wiring harnesses. All in all it was the kind of butcher job one expects at a fly-by-night shop, not a "Goodwrench" dealer.
Any help pointing me in the right direction on the evap. leak would be appreciated. I am going back to my fix-it-myself policy after the disaster of paying $1000 to have a dealership due a crappy job.
TIA, John
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Look for a loose line on the evap canister. I think that one is between the front panel and the radiator support, next to the A/C condensor.
--
Steve

"John Horner" < snipped-for-privacy@yahoo.com> wrote in message
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Steve W. wrote:

Thanks. I will check there. Considering all of the other problems left by the stealership replacement of the condensor your suggestion sounds very good indeed!
John
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