Hesitation during first 10 miles
 

I have a 1993 400E, I have been getting a problem of hesitation / bogging down after initial start up and for the first few miles, roughly 10 miles. It seems to start ok but has hesitation when I press the gas. I have changed the fuel filter, I ran it through a smog check station which it passed, but it was running ok at that time. I thought it might be the catalytic converters. I t seems to do it more so after sitting for a few days. Any help would be greatly appreciated. Thanks