Each burner and the oven come on correctly and light rapidly. However, if one burner is on and you try to light the next, the flame on the first reduces by half and the second burner barely comes on. If two burners are on, there is not enough pressure to light the third burner. When the third burner is opened up, the flames on the other two drop down to barely nothing. The repairman thought the problem was the gas regulator and he replaced it, but that did not solve the problem. We turned the water heater on while the stove was on (it;s also gas and right nearby), but that did not affect the gas volume at the stove at all. We are at a loss as to what is wrong. Any ideas? Thanks much!