Customer recently brought in his Mack E-7 350. Truck model is a CH613. Original complaint was hard starting and lack of power. Checked compression at a few cylanders, found low compression at 6,5,and 3. Rebuilt the motor, liners, pistons, rods, re-man heads from re-mack. Side note; heads were build without valve stem seals, called re-mack, they advised truck didn't need valve stem seals. Found out later from Mack, that in fact this truck absolutely needs them. I am having issues with engine surging at idle, wants to smoke at higher rpms, smells like fuel, installed new injection pump. Still having same problem. Engine almost stalls out after throttle depressed from high rpm. When surging it's around 650 to 900 rpms. Any suggestions?