Leaky Injector

Hello all,

I just received an oil analysis from http://www.oilguard.com/. I have about 7% fuel dilution for 1000 mile old oil. I’m thinking leaky injector. Here’s the story:

- The motor is a pineapple rebuild with about 4000 miles on it.
- The car is very hard to start when parked hot (shut off at 210ish or more degrees) unless - I hold the peddle to the floor. If I do this it starts almost immediately. After this, I just back off the throttle and everything is normal.
- There is always a small puff of black smoke when starting the car in the morning (cold start).
- I’ve been playing with my wideband and used it to dial about 8% out of the idle mixture to move the A/F ratio from rich to 14.7/1.
- The car idles with a very occasional small misfire.

Other info:
The injectors were specked / cleaned by RC engineering when the motor was rebuilt.
The car idles at 10-12 inches of vacuum due to a street port. Could this be the reason for the rich idle before the fuel dial out on my EFI piggy back?

So, anyone have ideas? How about a way to verify the injector problem without removing them? Other possibilities? (I’ve heard the loose side seal theory).