Todd, You do need to adjust the mixture if it was running reasonably well when it had the vacuum leak. That is un-metered air so someone probably adjusted the mixture to compensate for the extra air.

However you need to fix the cyl misfire first as that can upset everything else and you will have to go back and adjust the mixture again.

Adjusting mixture is a very easy thing to do after you have done it one time. I don't know for sure it you have a ECU or not and that will make a difference as how it is adjusted. I will try to explain how to adjust it if it doesn't have a ECU. All you need is a long 3mm allen wrench. Remove the air filter assembly. Just behind the air plate is a little 2 in high tower that is probably open on the top. With the engine running, put the allen wrench down in the tower. It should stop. When it stops, push it down carefully and turn the wrench back and forth until you feel it engage the adjustment screw. Turn the screw CCW just a little, maybe 1/8 turn or less. Remove the wrench and listen to the engine. If it is running better then try 1/8 turn again, removing the wrench each time. If it is getting slower or rougher try turning it CW 1/8 turn each time. 1/2 turn usually is too much in either direction. You have to just keep fine tuning until you get it sounding good.

When you get the feel of how to adjust the mixture, let me know and we will go into how I fine tune mine. It doesn't have a ECU because my engine is a EURO engine in a US car (long story). It never failed an emission test here in NC when they were doing them. Any car made before 1996 is exempt on the emissions now and gets a safety only inspection.

Paul

PS You may have to change the plugs. The ones you put in are resistor plugs. Some of these engines don't do well with resistor plugs. Mine doesn't like them. They cause a random misfire at idle when fully warmed up. I use NGK BP5ES.

__________________
84 500 SEL (307,xxx miles)