Intake manifold temperature creeping higher

"lfeatehr"...I was glad to see someone else monitors their intake temperature since Cummins doesn't look at exhaust temp. My 400 ISL always ran about 23-25 degrees higher than ambient temperature and never varied. My new coach runs about 30 degrees above ambient.

I don't know if you have an exhaust brake or engine brake, but I know when my exhaust brake was applied on my Monaco, the intake temperature would rise quite quickly. If you have the exhaust brake and it might be sticking a little.