Chasing a potential Bad Injector

[DRHaulsee]

My 2009 CX7(100,000 miles) posted a cylinder 4 misfire code several weeks ago. At the same time the dreaded timing chain rattle started. So, I ordered the parts and did the timing chain and VVT. Yes, the VVT was bad and the timing chain had just started to rub on the cover. It runs fine except the cylinder 4 misfire became more common. This misfire happens on cold start but disappears as the engine warms. I can reset the codes once it is warm and it doesn't come back until the next cold start.

I did new plugs with no change. Moved plugs around but the misfire stayed on cylinder 4. Swapped coil packs around but the misfire stayed on #4 . I bit the bullet and bought Cork Sport injector seals. When I took it apart there were no obvious signs of leaking injector seals.

When I reassembled it I moved the injectors around. #3 went to 1, #4 went to #2 , #1 went to #3 , and #2 went to #4 . Now I have a misfire on #2 . That tends to make me believe the #4 (now #2 ) injector is somehow "bad".

Have I missed something? How does a bad injector have this cold start behavior?

Oh, and I want to thank the posters here for the excellent write ups on the site. I've spent many hours reading through them.