Diesel Power Loss + Rough Idle: Fuel Filter Check Needed?

Had the exact same drama with my 2020 Chevrolet TrailBlazer diesel. The rough idle and power loss nearly drove me nuts. After some troubleshooting, turned out it was just a loose connection in the wiring harness to the fuel filter heater. Had it fixed at a shop, straightforward repair where they found and secured a damaged cable connection. Total bill was 95 for the fix. Engine runs perfectly smooth now, no more fuel system issues or stalling problems. Your symptoms sound identical, but could you share: Current mileage? Any recent fuel system work done? Does the rough idle get worse when the engine's cold? With diesel engines, these symptoms often point to fuel delivery problems. Could also be sensors or injectors, but start with the simple stuff first.

Thanks for sharing your experience. My Equinox has 86672 KM and just had its regular service last month. The rough idle is definitely worse during cold starts, especially in the morning. Haven't had any previous fuel system work done yet. Interesting that you mention the wiring harness, my fuel efficiency has dropped about 20% in the last two weeks, which lines up with when these issues started. The power loss is most noticeable when accelerating from a stop. Thinking I'll have them check the wiring connections first before looking at more expensive repairs. Quick question, did your check engine light stay on constantly or did it flicker?

The check engine light on mine stayed on constantly, that's actually one of the key indicators that helped pinpoint the wiring issue. Your symptoms match mine exactly, especially that cold start rough idle and the power loss during acceleration. When the fuel filter heater isn't working properly due to bad connections, it really affects cold start performance. The 20% drop in fuel efficiency you're seeing is spot on with what I experienced too. The engine management system tries to compensate for the fuel delivery issues, which leads to that higher fuel consumption. In my case, the engine would occasionally stall at idle when it was really cold, though this improved once the engine warmed up. Pretty sure you're dealing with the same wiring harness problem, especially since you mention the symptoms started suddenly. The good news is the fix should be straightforward like mine was. Just make sure they do a thorough check of all the connector pins, in my case, there was some corrosion on one of the pins that wasn't immediately visible. The cold start issues and power loss cleared up immediately after the repair, and my fuel consumption went back to normal within one tank of fuel. Let us know what you find, always good to have these real-world fixes documented for others with similar issues.

The wiring harness definitely seems like the likely culprit here. Mine stays on constantly, hasn't flickered once. Given all these matching symptoms, especially with the fuel efficiency drop, cold start issues, and power loss on acceleration, I'm now convinced it's probably the same problem. Got an appointment booked for tomorrow at my regular shop. Will have them start with checking those wiring connections and the fuel filter heater before diving into anything more complex. Makes sense to tackle the simpler fixes first, especially since it's exactly matching your diesel engine symptoms. Really hope it's just a loose connection like yours was, would be great to get this sorted without major expense. Will update once I know what they find. Thanks for the detailed comparison, it's helped narrow down where to start with the diagnosis. Just hoping for a quick fix to get my fuel economy back to normal and eliminate this annoying power loss issue.