Rfoster

Thank you for that info that gives me a place to start!

This is my first Mack I’ve had peterbuilts and kenworths all with Cummins motors so just a learning curve

Thank y’all for the help so far I’ll try to get pictures of the valve covers but I don’t see any wires to it I tried using the Jake brake and it didn’t do anything and as far as the running rough it has been idling fine lately but it still shuts off if you let it idle for a few minutes it will start right back up but when it shuts off a red circle with a x through it pop up in the dash and when I drive it today I noticed some blue/grey smoke when driving it does have some engine oil in the air tanks I can’t tell if it coming from the turbo or air compressor

While driving the truck you can feel it have good power at times then like it has no power

The engine must not have a Jake brake because I can’t find any wires attaching to the valve cover

No spacer under valve cover according to the data plate on the truck it’s supposed to be a e7 427 I’ll see if I can find the plate on the engine

Where is the engine id tag supposed to be?

It’s sporadic when it runs bad there isn’t a pattern to it I don’t see any wires going to the valve cover and 5 out of the 6 exhaust ports where the manifold bolts to the head it is wet right there

It’s got the button for a engine brake in the cab

I’m not sure I just bought the truck

I got those codes they were 3-5,3-6 which are codes for engine brake would that cause low power though?

I did it looks like I had something to do with engine brake the engine skips/ runs ruff at idle sometimes and sometimes has very low power just trying to figure out what’s going on it also shuts it self off when idling at times

My 2003 Mack ch is showing the codes 5079-05 m128, and 5080-05 m128 and idea what they are?