I'm in desperate need of advise for an ongoing engine issue. I have a '03 mercruiser 5.0 260 hp mpi. Earlier this summer the engine started hesitating and missing after about an hour or so of running. The missing seemed to get continually worse as the day went on, to the point of stalling out the engine. At idle speed it does not happen, but as soon as I get above about 2000 rpm it begins again. Also seems to happen more when under a load. The shop replaced the cap and rotor, spark plugs and fuel filter, all to no avail. Have had it back 3 more times and they can't seem to figure out why it's happening. Any advice would be greatly appreciated.
