Except for the current engine problem, I’ve really had good performance from my truck. When I rev up the engine, even slightly, there’s a short lag as the engine slows back down to an idle. It is briefly almost a muted sound and then it continues to idle. For some extra info: this truck had an upgrade of a 3” (approx) lift kit and also a magnaflow exhaust kit. The engine ‘mute’ has been occurring since before the magnaflow exhaust kit was done. What should I do to fix this problem?
You did not mention the engine you have in your truck, but I would suspect the engine turbo vane control is sticking when you rev the engine and will cause the engine to stay revved until the vanes go back to normal. If the turbo vanes are moving freely, then you may have a sticking idle valve and testing of the computer controls will indicate which system is causing the issue when tested. A qualified mechanic, such as one from YourMechanic will be able to diagnose your rough engine issues and let you know exactly what needs repair.