Hi everyone,​My name is Carsten, I’m from Germany, and I’m a passionate Dodge Ram 1500 owner (2016 model, 5.7L Hemi).​I’m reaching out because I’m struggling with a persistent issue and I’m at my wit's end. Since there are far more Rams on the road over there, I’m hoping someone might have a tip for me.​My truck runs on LPG (Propane) because fuel prices in Germany are quite high.​The Problem:The engine shakes/shudders while idling (at a standstill). However, it performs perfectly fine and has full power while driving. I should mention that the issue occurs on both gasoline and LPG. There is no difference in how the engine behaves regardless of the fuel type I'm using. I’ve scanned for codes, but no DTCs (Diagnostic Trouble Codes) are stored.​What I’ve already replaced/done:​Spark plugs and ignition coils​Oxygen sensors (O2 sensors)​MAP sensor​Crankshaft and Camshaft position sensors​Knock sensors​VVT solenoid (Variable Valve Timing)​PCV valve​Engine and transmission mounts​Smoke test (checked for vacuum leaks – none found)​The issue is inconsistent. Some days it runs perfectly. Other days, it starts shaking right after a cold start; then, two traffic lights later, it’s back to normal. It’s very frustrating because you can really feel the vibration inside the cabin.​I’m grateful for any advice or suggestions. I love this truck and just want it to run smoothly again!​Note: This text was translated, as my English is a bit rusty.


"I should mention that the issue occurs on both gasoline and LPG. There is no difference in how the engine behaves regardless of the fuel type I'm using."

​Thanks in advance,Carsten

 

Welcome to the forum!

Did this intermittent issue begin right after some work was performed on the truck, such as the dual-fuel conversion? Do you have the ability to datastream a few engine parameters, such as short-term fuel trims (STFT) and individual cylinder misfire counts?

-Rod

 

Thanks for your reply.​Yes, I was able to read the data, and the oxygen sensors (lambda sensors) etc. are regulating exactly as they should. I also uploaded the images to ChatGPT to double-check them.​I bought the vehicle with an LPG system installed, and it was running very well.​Unfortunately, there is no difference between running on LPG and petrol.​Since I’ve now replaced everything and there are no fault codes stored in the memory, I’m assuming that a control unit (ECU) is defective."