I am new to the forum and joined in hopes of getting advise on my timing chain issue. I have a 2000 540i sport with 130,000 miles. My check engine light came on a week ago and my BMW mechanic after testing stated that I need to replace the gas canister which he did. The charge was 700.00 A few days after I got it back the light came on again. I took it back and after testing he stated that the lower timing chain needs to be replaced for 2900.00. I am wondering if the first repair (gas canister) which was based on a code reading was related to the timing issue and may have been a false reading as a result of the engine trying to compensate. At this point I have not experienced any of the knocking associated with timing chain issues, however the mechanic did show me slack in the chain when we looked in the crank case. I dont want to pay additional money if he made the wrong repair. Please advise