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)
i BELIEVE that the misfires occur at low rpm's and thus it holds back off the line and then kinda kicks itself to a stable power curve.
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.
