Had a real scare this morning (and am now quite stumped). Was driving away from my favorite river fishing spot when the engine spluttered, stammered lost power, regained it again and lost power and stopped. Luckily I was on solid ground. Sounded like a fuel issue so emptied the contents of the fuel filter into a clean bucket (no fish this morning) and found water in there.


I now fear I have water in the IP and injectors.
I had a spare filter onboard so spun that on, primed it up, through the IP return, through to each injector and away I went. Laughing I thought I had come close to ruining something.
Acceleration is normal, aside from the intial black smoke on start up after priming, no smoking - normal, but out on the open road I cannot get the truck to go beyond 75-80kph.
Symptoms are hunting or starving for fuel, i.e. surge, lag, surge, lag etc. No perceptible missing in the engine tone, and no unusual smoke but rather, a lack of it. This 'no smoke' is an odd one as when I am normally cruising I can plant my foot and see the cloud of black smoke behind me (and then I ease back on accelaration till no smoke), this however is not the case anymore and I can push the loud pedal hard and no black smoke, no increase in engine revs, no change from the surge lag surge lag behavior till I ease right back and sit on 60-70kph (in fifth).
Idle - fine/normal and smooth, acceleration (both at rest or in gear on road) is as responsive as is usual and I don't (no matter how paranoid I now listen to the engine tone) hear any knocking other than the usual rattle. There is however a 'whirring' sound that follows the rev up and down with a little lag. I suspect this is coming from either PAS pump or the IP.
I have not got a tach onboard and so had to do some calculations and based on these I estimate the highway cruise symptoms appear at around 2600rpm. I tried inducing the surge lag surge lag in 4th and in 5th gear and at both recorded speeds (4th=~65kph, 5th=~ 80kph) calculations indicate about 2600rpm.
This motor has been very reliable and issue free up to stopping this morning. Prior to that (and in hindsight) there was a small stammering yesterday. I disregarded it as being a blunt truck travelling into a slight wind that may have hit a gust of wind - as it is that sort of feeling currently - a blunt truck driving into a very strong and gusty headwind - sometimes slowing quickly sometimes surging ahead.
Any ideas for checks before I start swapping injector and IP bits out from the spare blocks?
Cheers
Phil