check engine po303 cylinder 3 misfire only occurs under idle while ac is on on 2002 Ford Escape

changed cop/compression tested/noid test/ohm test all good.reset and code returns when ac is applied at idle for extended time. rough idle and jerky. misfire...

Asked by for the 2002 Ford Escape
Only thing left is a vacuum leak near # 3
probably the only thing I haven't checked for yet, however the engine runs smooth under all conditions,until the ac is applied. I will try the vacuum leak angle just to be sure. Thank you for the quick response.