CTS Misfiring at Idle: Bad Ignition Coil Guide

Had similar symptoms on a 2015 Cadillac ATS with the 2.0L turbo engine. Vehicle diagnostics confirmed multiple cylinder misfires. The engine hesitation and power loss were caused by deteriorated ignition coil packs. The ignition system repair required: Testing each coil pack with specialized equipment, Replacing two failed ignition coils, Installing new spark plugs as preventive maintenance, Checking all connector terminals for corrosion, Clearing the check engine light and verifying the fix This was a significant repair that took about 3 hours of labor. The symptoms matched yours exactly, rough idle, stalling, jerking during acceleration. The unusual misfires can damage the catalytic converter if left untreated, so addressing it promptly is important. Would recommend having all coil packs tested, not just replacing one. Often when one fails, others are close to failing too. The connector terminals should also be thoroughly inspected, as corroded connections can cause similar symptoms.

Thanks for sharing your experience with the coil failure issue. My Cadillac CTS had the same symptoms last year, rough idle, misfiring, and that dreaded check engine light. The ignition system repair fixed everything completely. Just wondering how much you ended up paying for the full service? Also, have you had any other ignition-related problems since getting it fixed? My car has been running great after the repair, but Im always curious to hear about long-term reliability from others who went through the same thing.

Since getting my CTS repaired last week, the ignition coil issues have been completely resolved. The mechanic found a faulty connection in the ignition system that was causing the misfiring and stalling problems. The repair bill came to 95€ for fixing the defective cable connection to the coil pack. No other ignition-related problems have surfaced since the fix. The engine runs smoothly now without any hesitation or power loss. The spark plugs were also inspected during the service and found to be in good condition, so no replacement was needed. The most important thing was catching the failing ignition coil early before it could cause damage to other engine components. Regular maintenance of the ignition system components really pays off in preventing these kinds of issues from recurring.

Thanks everyone for the helpful replies. Finally got my car back from the shop yesterday. The vehicle diagnostics confirmed what you all suspected, it was indeed a failing ignition coil causing the misfire issues. The mechanic found two damaged coil packs and replaced them along with the spark plugs. Total cost came to 320€ including parts and labor. Much better than my last mechanic who wanted to replace the entire ignition system! The engine hesitation is completely gone now and it runs like new. No more jerking or stalling at idle. The shop also showed me the worn coil packs they removed, you could actually see the deterioration. Really glad I dealt with this promptly instead of risking damage to other engine components. Will definitely keep a closer eye on the ignition system maintenance going forward.