I have a '89 260E with 130K miles on it. Lately, it has been having rough start and idle problems. I have since changed the O2 sensor, the EHA, plugs, both fuel pumps, fuel filter, injectors, and the air filter. It has since been running much better, but still has a rough "baubling" /engine bucking effect for about 6-10 seconds after starting.
The weird thing is that the the roughness gets worse as the car is started throughout the day, rather than initial start-up in the morning. Seems also to get worse during warmer weather.
Once started, everything works fine. Just would love to work out these minor bugs. Any suggestions on what to replace next?