Hi Paul:
From what I gathered, the fuel pumps make a growling sound when failing. Could a fuel pump or pump relay fail in a way to cause these problems? It isn't an issue after the first couple of minutes, or starting the car when it is cold. Just when restarting within 1/2 hour of driving, mostly on warm days. Strange.

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John

2003 Firemist Red/grey leather SL 500
2015 Palladium Silver/black mbtex GLK 350
1987 Smoke Silver/burgundy mbtex 300E Sportline (SOLD)

Click to see 87 300E