BMW Questions? Ask a BMW Repair Expert for Answers.
Hi, First I assume we are talking about the 2.8L Engine? These older heads go bad real quick when overheated, so that worries me on your case. Second You stated you put plugs in? Ive had several cases where the coils were not plugged in absolutely secure, They will visually appear to be connected but need a little more pressure applied to get them to snap secure. The Snanner communication failure is common on cheaper scanners, have you verified yours does in fact work on other BMW's ? Are you using the OBD2 plug under the dash or the BMW factory port under the hood?
If you have the BMW connector for your scanner use that, its on the left strut tower area. Coils are common to fail on these. The PCV(purge valve) under the intake is super common to get stuck open and will cause a surge. With engine running open oil fill cover and feel if you have excessive vacuum in the engine or the idle changes at all when removed.