Bogs for a second and then takes off

[StickWalker]

First off, I replaced the injectors with new FIC injectors and pinned the secondaries open with Hiabecks chip for 2ndy deletion. I did this swap around 500 miles or so ago and also changed the fuel filter at the same time.

Now the issue starts after a few minutes of driving before that it runs great. (Never has an issue from a stop) When the issue occurs I am in a gear coasting (foot off the gas) at around 2-4000 rpm, and when I hit the gas pedal it bogs down for a second or so and then takes off and pulls to 7000 no problem. It only ocurrs after a moment of high vacuum once its warm. I have replaced the MAP sensor and hose with no change, drove around with a fuel pressure gauge on the windshield which shows around 41 psi with the foot off the gas, and goes up to 51 when I press on the gas.


I've checked for vacuum leaks and cant find any. The only thing I have noticed is that #4 cylinder plug seems like it's running rich, Ohm's 16 when cold, havent checked when hot.

If anyone has any other ideas without just throwing parts at I would appreciate it.

Thanks,
Don