2008 BMW E92 M3 misfire and valve spring replacement
The owner reported a sudden misfire and limp mode, followed by cylinder 3 losing compression after work on cylinder 4. He later said the dealer replaced a valve spring and the car ran normally when returned.
Cylinder 4 stopped firing during a short drive
The owner said the check-engine and increased-emissions lights appeared and the car entered limp mode about 200 feet into a drive. Dealer diagnostics found cylinder 4 was not firing. The dealer changed its coil pack and spark plug without restoring it; after further troubleshooting, cylinder 4 fired again, but cylinder 3 then had no compression. The thread does not explain what restored cylinder 4 or provide codes or test readings.
The owner reported a valve spring replacement
The owner said the dealer first considered a valve spring and later confirmed that diagnosis. He reported the dealer removed the cam and waited for a special tool. After getting the car back, he said the dealer had replaced a valve spring, which he identified in the post as the “#3 exhaust lifter #6 spring,” and that the car ran well. The thread does not give the part number, invoice, detailed repair steps or a measured follow-up.
A commenter described a separate warning-light case
gatoraviator recalled similar warning lights on a different car and thought its fix may have been an idle-control valve, but could not remember the repair with certainty. aus said that did not sound like an idle-control-valve failure. The original poster later reported that his dealer identified a valve spring. These were separate cars and do not establish the same fault.
Source reply ↗ · gatoraviator
Source reply ↗ · aus