Car won't start without pumping gas pedal, so was advised to replace cold start valve. (Car seems to run well once started, and idles down to normal within a few seconds of starting; only other thing I see is sometimes sluggish accelerating away from a stop until the revs get to
1500 to 2000 range, then acceleration is very solid and quick.) Web sites selling parts show 2 different O-rings that should be used with replacement of cold start valve. Is this something I can do in my driveway? That is, given the existence of the O-rings, when I loosen the 12mm fitting on the top of the valve, is the fuel in the line under pressure? I had some difficulty busting loose the two 5mm hex head bolts that anchor the valve to the block, but that is out of the way. Anything I should be aware of before continuing? Do I need to prime the line in any way when reassembling? If I replace the valve and it still won't start without pumping the pedal, what should I look at next? Thank you for your time and input.