Rough running 300 HPDI

[APM]

I have two 2004 300 HPDI's on the boat and when I started them up one started just fine on the first try but the other one did not. It took three times before it would run on it's own. It was running as though it had dropped a cylinder. After it warmed up it seemed to run better but when I throttled up the first ran up to 4500 r's but the other only made it to 3500. Checked the spark plug wires but all seemed ok. Naturally just got it out of the shop and they are saying they did not touch the motors. At a loss - hope it's an easy fix - really don't want to go back to the shop.

[mitch]

has the o2 sensor been serviced

linky thingy
http://www.boatsetup.com/O2sensor.pdf

[APM]

Thanks Mitch - I'm going to take it in to the dealer in the morning and I will bring up the o2 sensor along with a couple of other things.