Cadillac STS Cold Start Issues, Fix and Costs Revealed

Had a similar issue with my 2011 Cadillac CTS. Started with hard starting issues, especially during cold starts, and the rough idle was really noticeable. After some basic troubleshooting, my mechanic ran a thorough injector test which revealed a faulty fuel injection unit. The testing process was pretty systematic. They first checked for basic issues like fuel pressure and spark plugs before focusing on the fuel system components. The diagnostic equipment showed irregular fuel spray patterns from one of the injectors, which explained the rough idle and starting problems. The fix involved replacing the defective injector and cleaning the entire fuel injection system. Total cost came to 515€ including parts and labor. Since the repair, cold starts have been smooth and the rough idle completely disappeared. Before suggesting specific solutions, does the check engine light come on? Have you noticed any decrease in fuel efficiency? Are there any unusual engine sounds during idle? Has any previous fuel system maintenance been done? What kind of fuel are you using? This info would help determine if your symptoms match what I experienced and whether you might be dealing with a similar injector issue.

Last service at 66922KM. The check engine light actually started flickering recently, and fuel efficiency has dropped noticeably. The fuel rail pressure seems inconsistent based on the diagnostic readings I got. When running an injector test, my mechanic noted irregular spray patterns similar to what you described. I have been using premium gasoline consistently, but the rough idle persists, especially after cold starts. No major fuel system maintenance has been done since I bought the car, which might explain these issues. The engine does make a slight ticking sound during idle, particularly when cold. These symptoms do sound very similar to what you experienced. Did you notice any warning signs before the injector completely failed? Also, was your repair done with OEM parts or aftermarket components?

Your symptoms definitely match what I experienced with my CTS. Before the complete injector failure, I noticed increasing inconsistency in engine performance, particularly during cold starts. The engine misfire became more frequent, especially in the first few minutes of operation. The irregular fuel delivery you mentioned, combined with the ticking sound, strongly suggests injector issues. In my case, the flickering check engine light was directly related to unstable fuel rail pressure, which matches your diagnostic readings. For the repair, I opted for OEM parts after discussing options with my mechanic. While aftermarket injectors were cheaper (around 280€ versus 390€ for OEM), the potential compatibility issues weren't worth the savings. The complete fuel injection service included: Replacing the faulty injector, Professional injector cleaning for the remaining units, Fuel rail pressure sensor check, System pressure test The ticking sound you described disappeared immediately after the repair. The improvement in cold start performance was dramatic, from multiple attempts to instant starts. Given your car's mileage and lack of previous fuel system maintenance, I would strongly recommend a complete fuel system service. This preventive step helped avoid similar issues with the remaining injectors in my case.

Thanks for the detailed information about your repair experience. The similarities between our issues are striking, especially the cold start problems and fuel system diagnostics. After hearing about your successful repair with OEM parts, I am leaning towards taking the same approach. The ticking sound and engine misfire symptoms you mentioned match my situation perfectly. Your point about the fuel rail pressure issues makes sense, considering my diagnostic readings. A complete fuel system service seems like the smart choice, given my car has never had major fuel injection maintenance. My mechanic recommended similar steps to what worked for you, replacing the problematic injector and servicing the entire fuel system. The price range is also comparable to what I was quoted. Think I will schedule the repair next week and opt for the OEM parts to avoid potential compatibility problems. The fact that your repair resolved both the rough idle and hard starting gives me confidence this is the right path forward. Will make sure they do the complete fuel system check and cleaning as part of the service.