What are the symptoms of bad injector o-rings? I have a 99 PSD I put new glow plugs in it and while I had the valve covers off I started it to see if everything was ok and I noticed oil coming out of the spill spouts on the injectors but there were three of them that had no oil coming out. Why would come out of some but not others? The truck has 204k miles on it and it doesnt seem to have the power it used to have. Thanks for any help.