if you did not start with FULL secondary filter, after starting the car on the new primary, and building up fuel... then you have air in the IP, and injector lines, and need to bleed them all out.

proper way to change both filters is: replace the clear primary, then start the car, and build up smooth idle.
then shut down the car, and remove the secondary filter, with the new filter already filled with fuel, and ready to install.
install it with new o-rings on the center bolt, and crank the car, with the accelerator 1/2 pressed down to cover the stumble as air is ingested, and let up once the stumble is gone.

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John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 560SL convertible
1987 190D 2.5-5SPEED!!!

1987 300TD
2005 Dodge Sprinter 2500 158"WB
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!