Throughout the past two weeks I've went through a cycle of pulling my intake, replacing my fuel injector grommets, putting it back together, and then having a car that runs perfectly for about 3 days. After 3 days, sometimes less, it'll start running really rough and sound like there is a vacuum cleaner running under the hood. I have to repeat the process and then it is fine. Sometimes I don't even bother replacing the grommets; I just re-seat it all and then it runs well for the same length of time.

It is only the primary fuel injectors that are developing the leak. I don't/can't see why this would be happening. When I pull them the only thing "strange" is that one of the grommets is usually stuck in the injector hole. I think it is slowly getting sucked down too far, off the injector and then maybe it is allowing some air to squeeze by the pintle cap? Any ideas or suggestions?

 

Are you using the OE injector insulator/grommet?

 

Is there a small plastic spacer where the fuel rail mounts to the engine?

 

OE grommets and the insulator is there as well. I had to order a new one because I had been using washers instead and still had this issue.

 

which injectors? I bought these big o rings online. I think they are fuel injector o rings meant for a Porsche or auto or something like that. The factory grommets don't seem to go to well with some aftermarket injectors

 

It could be leaking air past the diffuser O-rings