Got a 90 740 GLE station wagon (missing its rear muffler at present) that turns over yet doesn't like to start up on the first or second try. It has also stalled out at stop signs, and once when driving. Had a tune up about 3 months ago, new plugs and plug wires, and some welding on the exhaust, but the muffler is still missing. Could the exhaust be causing this in any way? It always eventually starts. Could use a little more power, but, hey, it's a 22 year old car. Could this be a fuel pump or fuel filter issue?

Any ideas are greatly appreciated!