255 lph intank pump is more than adequate. I would not go with an additional pump. There is a problem. You should be running 40 psi vacuum off then connected at idle with no problem. I would at least temporarily put in a mechanical fuel gauge. I have mine on the hood in front of the windsheild. They cost like 35 bucks. If you have stock injectors in there with the stock MAF, do you also need to have the fp high like that? Are you sure what you are measureing the a/f with is correct? Sounds like you have your maf set in there nicely. When I had my car tuned, my pmas 75 mm was on the lean side. I had my fp at 45 vacuum off. Bottom line is you should not need that much fp to idle. If you back off on the fp, does the car idle poorly? My car was reading about 12.5-13 at idle. They go somewhat lean NOT under load as the rpms go up. But as soon as you hit wot, you should be down around 12-11.
97 Laser Red GT-248A Wingless model, Built Lincoln Mark VIII motor-Procharger D1SC, 3 core IC
2012 Black GT-Saddle, 3.73s, Brembos, Shaker1000