sputtering motor after warm up?

[85'325e]

hey yall, new member here from wisconsin. anyways i have recently become the proud new owner of a 1985 325e 5 speed manual. i absolutely love my black beauty but unfortunetly a few things have been going wrong with it. for starters my heater core blew out...not a big deal until winter comes. than a few weeks after that i noticed that my newly replaced spark plugs closest to the fire wall were getting moisture on them. could it be possible that i didnt gap them correctly? now the most recent problem...my motor begins missing horribly.. most of the time after it warms up. (sometimes when cold as well). ive been searching the forums trying to troubleshoot my issues. so far i have heard that changing my coil pack would fix my missing motor. waht i need to know is 1. where is my coil pack located, and can i find a schematic diagram of it on the web? and 2. Is it possible for a shade tree mechanic like myself to replace a coil pack, without major labor included??

Any suggestions would be greatly appreciated!!

[m20enginebuilder]

The M20B25 engine does NOT have a coil pack for starters, it has 1 coil, and a distributer located on the front of the head. The rotor bolts directly to the cam pulley for the timing belt. Ill get into the timing belt in a few mins. But now for problem A. Id suggest taking off the distributor cap and rotor. Inspect, and file/sand as necessary, test, and see if it works better. Another thing to do is CHECK to see where your getting gas, and MAKE SURE it has 10% ethanol like it says it does. Here in Colorado we have 0 ethanol gas availible to us, and thats what i run in my E30. Also, id check the injectors too. Ethanol is TERRIBLE news for injectors, because it corrodes them and causes sticking. If none of these help, try filling completely with your highest octane fuel, and then put some Seafoam fuel system cleaner into it. Also, do you have a check engine light? Also check the resistance of all 7 ignition wires. It should be about 10,000 ohms per foot. Another thing to check is the vacume actuated fuel pressure regulator, fuel filter, and fuel pump. Now about that timing belt. I know you ARE NOT having issues with it, BUT BMW recommends a replacement every 50,000 miles. The best thing to do is ASK the previous owner WHEN it was repolaced last, and if he/she is unsure, GO IN and replace the timing belt, tensioner, and water pump. The water pump is sposed to be changed when the timing belt is, even tho it is not driven by the timing belt. The reason is is because the M20 is an "interference" type engine, which means if the timing belt breaks, your lookin at bent valves, and broken rockers, but thats the least of your worries, going from there, damaged head, and broken pistons. Ive looked at new heads, BMW oem ones go for about 1500 a pop off of Pelican Parts. And the pistons are about 1200 a set, but thats for aftermarket ones of the same stock compression ratio of 8.8:1