Challenger Boost Issues Killing Performance & MPG

Had a very similar issue with my 2014 Charger last year. Having some experience with turbo-related problems, the symptoms you describe sound familiar. My car showed the same issues, poor acceleration, increased fuel consumption, and inconsistent boost pressure. The root cause turned out to be a faulty bypass valve connected to the intake manifold. The pressure sensor was giving incorrect readings, causing the boost solenoid to malfunction. The fix involved replacing the vacuum switching valve, which cost 140€ including labor. After the repair, the throttle response returned to normal and the engine regained its original performance. What specific error codes is your check engine light showing? This would help pinpoint if your Challenger is experiencing the same issue. Also, have you noticed any unusual sounds when the turbo spools up? These details would help determine if your problem matches what I encountered. Worth checking the pressure sensor readings if you have access to a diagnostic tool. It can reveal if the boost control system is getting accurate data to work with. What model engine does your Challenger have? Knowing the engine specs would help provide more specific guidance about potential fixes.

Latest service was at 135000 KM. The diagnostic showed code P0299 which points to turbocharger underboost. After checking the intake system, found several split vacuum lines causing inconsistent boost pressure. A compressor surge was also noticeable under hard acceleration. The boost controller seemed unable to maintain stable pressure due to these vacuum leaks. The turbo lag has gotten significantly worse over the past few weeks, especially during cold starts. Have scheduled a repair to replace the damaged vacuum lines and conduct a full pressure test of the system next week. Would recommend having the mechanic check both the bypass valve and vacuum lines thoroughly, as these components often deteriorate around this mileage.

Thanks for the update about the P0299 code and vacuum line issues. Your symptoms match exactly what I dealt with on my Charger, those split lines can definitely wreak havoc on engine performance. When I had the pressure test done, they actually found multiple small vacuum leaks that were causing compressor surge, just like yours. The engine performance improved dramatically once all the degraded lines were replaced. The total system pressure drop was significant before the repair. One thing to watch for: make sure they inspect the pressure sensor connections while doing the vacuum line replacement. In my case, a loose connector was contributing to erratic boost control, and it was an easy fix while they had everything apart. The turbo lag you mentioned during cold starts is a telltale sign. Once my vacuum leaks were fixed and the boost pressure stabilized, that morning sluggishness completely disappeared. The repair cost me about 280€ for all new lines and labor, but the improvement in performance and fuel economy made it worthwhile. Have you noticed any whistling sounds from the engine bay? That was another symptom I experienced before getting the vacuum system sorted out.

I appreciate everyone's insights. Got the car back from the shop today after the vacuum line replacement and system testing. The P0299 code is now cleared and the turbo lag is completely gone. The mechanic confirmed multiple vacuum leaks were causing the boost controller to behave erratically. They replaced all the deteriorated lines and performed a comprehensive pressure test to verify the system integrity. The compressor surge issue during acceleration has been eliminated. Total repair cost came to 320€ including parts and labor. Definitely worth it, throttle response is crisp again and fuel economy has improved noticeably. The bypass valve was also inspected but found to be functioning properly. For anyone experiencing similar symptoms, having the entire vacuum system checked for pressure drop issues saved me from potentially more expensive repairs down the road. The car now pulls strong through all gears with no hesitation or boost inconsistency.