Hello, first-time poster and of course it's cuz I have a problem. I promise to follow up though!

The vehicle is a 2003 F-350 with 6.0L - all stock. I bought with 113k miles and have added 27k miles to it - so we're at 130k now.

I haul a 3,000lb truckbed camper most of the time.

The issue started yesterday going through the mountains in Colorado around Delta. I am cruising along and the first thing I notice is my tachometer acting sporadically. I then start to pay way more attention to everything and realize it's not the tach failing - but that it is indicating to me that the engine is sputtering/surging a bit. I pull over and get out, pop the hood and listen - at first at idle it is trying to "find home" but is jumping around RPM a bit, then it settles down and idles ok, but when I give throttle it will lose it again.

I limp back 10 miles to the last town, visit a mechanic who is booked out for 2 weeks but willing to talk with me for 15 minutes or so just to get some ideas. I cruise around with Torque Pro on most of the time to watch the EOT, ECT and HPOP - and because I'm a nerd and like to see the stats. Those all are within the normal operating range, the ECT/EOT is a little high for my liking but not off the charts and I've been up and down big passes hauling some weight. (210 ECT and 220EOT while climbing, 195 ECT 205 EOT while flat, and lower when descending and the engine isn't working hard). HPOP is 650 at idle hot and 700-725 at idle cold, duty cycle on the ICP at idle is ~20-22%. Also I just put in a new FICM myself as a preventative maintenance item about a month ago and we got 48-48.5 volts consistently there as well. The old one was sporadic between 30-42volts - ran fine but I figured it was on it's way out. FICM Sync once I added it to Torque reports 1.0, this was not during the issue down the road but sitting still at idle and revving to ~3000 RPM.

At first I am getting no codes, but after limping back the 10 miles to talk to the mechanic and then another 20 miles to a larger town with a mechanic that can get me today I first get a Crankshaft Position Sensor code, followed by a Camshaft Position Sensor code, a Fuel Delivery Error, and a Misfire on every cylinder. My first thought is it's a cascade of errors that started with the Crankshaft Position Sensor that then caused the other ones to follow. Today we (the mechanic) are digging down to the Crank/Cam sensors to test them and replace if they are bad.

After turning the engine off and back on it will start up right quick and idle just fine, but once you start to go down the road and get any amount of load on it for very long the issue returns.

I reckon my ask here is - any others with similar situations before that have advice on us being on the right track? I've read that wire chafing could be an issue making the codes for the sensors show up. They said they would test the sensors before just replacing them so if the sensors test good, we look closer at the wires?

Thanks for any feedback, words of advice etc..

Cheers,
ry