Install a Wide Band O2 gauge, with this type of gauge you will know EXACTLY what your air fuel ratio is at all times. I suspect you are running lean in the problem areas. The AEM 30-4110 is a good gauge for the money.
If you send me an email
sal.carceller@cox.net I'd be happy to send you a sheet I created for gathering 7 test cases with AFR numbers. But you must have a WideBand O2 gauge!