Hi, I am a Newbie to the forum. I have an Audi A4 Quattro 2.8L that starts very hard after it is left for over 8 hours. It can take up to 10-12 starts before it runs continuously and it the meantime it sorts of sputters, shakes and then dies. Once it is running it runs great and I can fully depress the gas pedal without running lean on fuel and if i turn it off and restart it with an hour or 2 no problem. My diagnosis was that I have a low fuel pressure in the rails upon start-up. Since then I have replaced the fuel pressure regulator and it is still not starting correctly. One question I have is that when you put the key into the ignition position should the fuel pump run? Mine is not running. Once it starts up I can hear it running fine. Any help anyone could provide in troubleshooting this would be much appreciated. Thanks!

 

did you clean your mass air flow sensor? How long has it been since a new fuel filter? The car should only run the fuel pump once for a sec on key on, after that you would have to wait a few to get another one.

 

pulled the MAF sensor off and it is clean as a whistle and then kept going and cleaned out the throttle body. It was a little gunked up in there. It started up fine after cleaning, but it was not exactly a cold start. Will restart it in the morning and see how it goes.

 

Can u send me a pic of that sensor and how to clean it? I also have some vibs in idle any idea? it's A4 1.8 99