help... 1996 318is ... misfiring

[sabbath130]

hello all, name is zack and havent been around in a while.
my 1996 318is m44 supercharged bmw has three check engine codes that i cannot fix. 1- random multiple misfire 2- cylinder two misfire 3- cylinder three misfire. on my boost gauge i am reading between 15-17.5 inches of helium at idle, believe a healthy engine SHOULD be approx 20.

i have taken multiple steps to try to fix the problem:
1- new coil pack
2- new spark plugs
3- new spark plug wires
4- new throttle position sensor
5- cleaned idle air speed control valve
6- checked for vacuum leaks.
7- replaced air injection hoses.
8- warm and cold compression test= never below 192 on ANY cylinder

sometimes when i go from in gear to rolling in neutral the rpm's will bounce before maintaining a steady idle speed. (the vacuum pressure bounces with the idle)

all in all... the car ran a 15.6 on the 1/4 mile (before a few of the fixes) and i spun all the way through first gear. car is drivable but definately holds back.
please help me becaue i am out of ideas.

[87esir]

possible vacumn leak problem, check replace all hoses
possible cam wear problem, wear on the cam will cause strange vacumn readings.
are you running good plugs and gasoline that is adequate for your engine? Boost means you need better fuel or you may cause engine knocks thus codes!

[sabbath130]

Originally Posted by 87esir

possible vacumn leak problem, check replace all hoses
possible cam wear problem, wear on the cam will cause strange vacumn readings.
are you running good plugs and gasoline that is adequate for your engine? Boost means you need better fuel or you may cause engine knocks thus codes!

i was using too thin of an oil for a while. but other than that i have ALWAYS used premimum gas or 94 octane. and i am using bosch +4 plat plugs.

could thin oil cause cam wear?

[87esir]

not in general if it was a quality oil. You do not want a light weight oil on that turbo in the summer though. I always use 20/50 in the summer because those turbos will roast your oil.
If you engine has high miles or hasn't been taken care of by previous owners you might have a little cam wear. Unlikely that is the problem unless like I said you have really high miles or maybe that engine is hard on the valve train.