Hey Scotty, I have a 2007 Dodge Ram 1500 with 223k miles on it and it has a brand new remanufactured motor. It makes this weird tapping/stuttering noise from a cold start once the engine gets down below 1000rpms. I took it to a mechanic to fix an exhaust leak is what they suspected and it is still doing it even after I took it in. It completely stops once the truck has warmed up and I can’t figure out for the life of me what it is.
It could be a bad hydraulic lifter. If you remove the valve covers and spin the motor, all the rocker arms should move the same. If they don't you have a bad lifter.
Is there any way I could send a video of it to you? It’s not like a continuous noise like a hydraulic lifter sounds like, it only does it once every 10 seconds for like a minute or so since it gets below 1000rpms and it’s just like a little stuttering noise from the exhaust. Once the engine heats up it completely goes away. The exhaust actually will shake a little when it does it and my rpm’s will fluctuate very very slightly, nothing super noticeable in the idle
Upload your video on Youtube and share the link here.
The video is titled: “Sputtering noise from exhaust below 1000rpms on a cold start. What is it?” Incase it won’t work in the link and you have to look it up. https://youtu.be/f__udAE_ovo
that’s the link