About 2 weeks after replacing a failed injector Im getting this loud rapid tick from under the valve cover. The car has been hard to start in the mornings as well. The sound starts once the car starts to get warm and when it is warm. For a few days it went away but now it just getting worse and worse. I have changed the oil twice since the failed injector flooded the cylinder and pulled the valve cover to see if anything looked wrong but nothing seemed bad. Today I looked down at the boost gauge and at idle it was only reading 10 in/hg instead of the 18-20 it normally reads.
The car is still running quite strong though so I am puzzled as to what it is. It sounds bad though. Any help would be greatly appreciated.

 

it sounds like a sticky valve, but who knows. Did you try flushing the motor? that might break up gunk if you have something sticking.

 

I did a chemical oil flush a few times and cleaned the oil pan. Then filled her up with some new 10w40 and the sound has subsided greatly. Its still a bit difficult to start in the mornings but that may be related to a possibly weak battery as the auto seatbelts are very slow in the mornings too.