Buick's Limp Mode & Rough Idle Points to Throttle Issues

Having some experience with engine issues, I dealt with similar symptoms on a 2015 Buick Regal (if yours is a different model, let me know which one you have and the year). My car showed the same signs, reduced power, limp mode activation, and poor engine idling. After initial troubleshooting, it turned out to be a faulty accelerator pedal module. The response delay between pressing the pedal and actual acceleration was the main red flag. The repair cost came to 265 for parts and labor, and it resolved all the symptoms, the rough engine idling, power loss, and check engine light. The fuel efficiency also improved after the fix. Important to note though, similar symptoms can have different causes. Could you share: Exact model and year, When did these symptoms first appear, Any specific patterns (does it happen when the engine is cold/warm), Any other warning lights besides check engine, Current mileage This info would help narrow down if your issue matches what I experienced or if it might be something else.

I have a 2010 Park Avenue with 44172 KM on the clock. The throttle body symptoms started happening right after my latest service about 2 weeks ago. The limp mode kicks in mostly when the engine is warm, usually after 15-20 minutes of driving. No other warning lights besides the check engine light. The rough engine idling seems worse in the morning. Thanks for sharing your experience, sounds like it could be something similar, though my symptoms are a bit different from what you described.

Thanks for the additional details. After reading your specific symptoms, I suspect our issues might be different despite similar warning signs. On my 2015 Regal, the response delay and reduced power were consistent regardless of engine temperature, while yours seems to worsen when warm. Given that your symptoms started after a service, and considering the behavior pattern with warm engine conditions, I lean towards a throttle body issue rather than the accelerator pedal module that was my problem. The rough morning idle particularly points to the throttle body, which I learned while troubleshooting my own car. The throttle body replacement on these engines typically costs between 300-450 for parts and labor, more than what I paid for my pedal module fix. The good news is that replacing the throttle body often improves both fuel efficiency and eliminates that frustrating check engine light. Before committing to the repair, you might want to have a mechanic check if the throttle body just needs a thorough cleaning, sometimes carbon buildup after service can cause similar symptoms, especially with the air intake system involved. Would you mind sharing what kind of service was done before these issues started? This might help pinpoint if something during the service triggered the problem.

Based on your suggestion about the throttle body cleaning, I should mention the last service was just routine maintenance, oil change, air filter replacement, and brake fluid top-up. But what concerns me is they might have disturbed something while working around the air intake system during the filter change. The rough engine idling has gotten slightly better after running the car for longer periods, which makes me think you could be right about carbon buildup. Plus, the air flow seems a bit restricted compared to before the service. I will try getting the throttle body cleaned first before considering a full replacement, that price range you mentioned for replacement is pretty steep compared to a cleaning service. Good to know about the potential fuel efficiency improvement too. I will update the forum once I get it checked out and cleaned. Thanks for helping me narrow down the possible causes.