I just took out my stock injectors (93 Civic EX ~99k miles) to put in some slightly larger 290's and there was an unbelievable amount of crap around the injectors! I use chevron all the time and use their fuel system cleaner every couple months and there wasn't anything right around the tip, but just inside the manifold on the injectors was a good 2mm? of sludge that seems almost like dirt and oil...it's not from the outside because the seals were clean...it almost seems like oil on them, but that's weird and what's more weird is that the inside of the manifold is perfectly clean. any thoughts? I'm running a bit rich and I have a high-flow( non K&N ) filter on there now and noticed some dust on the inside of the joint, like some small particles are getting through (getting new filter very soon!)

 

its called the valve cover vapors. There should be a hose from your VC to your intake. I have pulled injectors with 30k miles and they have been gunked with sludge. No big deal.

 

thanks, I've never pulled my injectors before, so I didn't know, but it makes sense. glad it's no biggie.