[laiman]

Replaced the valve cover gasket this weekend and while i was at it i replaced the valvetronic gasket and the ignition coils. Id intended to do the spark plugs as well but got sent the wrong ones.
Yesterday I replaced the water pump and thermostat as those werent working and now they work as intended.
However leaving the garage and going up the hill my car started to buck and thrash at low speed. Used a c310+ scanner to check codes and it marked the engine as having a code but when i try to read it it says no fault codes found.
The engine valve cover is also missing to bolts as the previous owner /s mechanic had sheared off two bolts in the lower left side close to the vanos. (Left if viewing from the front of the car.)

Could the issue be the new coilpacks? Have the sparks just died? Or coule the missing bolys be causing a problem?
I also noticed a hissing sound by the oil filter housing/brake booster hose. Possible vaccume leak there?

The car bucks aggressively in low rpms. especially in 1st when climbing hills or parking. If kept at around 30mph in 3rd gear it smooths out. Low rpms in second gear also cause the car to jump/jerk around.

Replacement coils were Bosch and has the same part number, but the ends looked slightly different to the ones in the car and the contact point inside looked more recessed.

I also have battery exhausted codes. When ******ting a charger it shows low battery.

Where should i start fixing the bucking? Wasnt acting like this before I changed the valve cover gasket and coils.

Worth noting the tachometer during these bucks goes a little wild and can jump up and tank down to 0 for a split second before smoothing out.

[lookalikehuuh]

I would get a better scanner to try to read the true BMW codes if your OBDII scanner is having trouble reading them.

Where did you purchase the parts from? The quality of the replacement parts could play a huge roll in how the vehicle is running currently. Also if you hear a hissing noise and you thin a vacum leak is present you should defintely chase that down as it could make the vehicle behave in the exact manner you are describing.

[lowrydr310]

Until you can read the BMW codes, make sure the coils are seated properly and that the electrical connector is fully inserted into each one. There's a little trick where the plastic clips on the coils have ears that grab the connector and pull it into place. My first time working with the coils on this platform I had a few that weren't seated properly causing some similar symptoms.

Also check that the ground strap near the coils was reattached. You likely removed this while replacing the valve cover gasket - just another easy thing to check that's worth verifying.

The hissing isn't good. Were you certain the valve cover was installed properly and the gasket wasn't kinked or folded? Fix those broken bolts too; hopefully you removed what was left of the broken bolts in the holes when you had the valve cover off.

[schwing]

Since you removed valvetronic motor to replace gasket, you might need to perform reset of throttle body adaptation.

Video:
https://www.youtube.com/watch?v=x45LHTfdgS4