OIG and WAMMER - dispicible bickering like children on a thread where a guy needs help...
Given the OP stated it smokes a bit and is gutless I suspect it is a boost problem, either it is making boost at the turbo but not at the manifold, sounds like a damaged / fallen off intercooler / hose, or it is an issue with the VNT section of the turbo not being able to move, which would tie in with one of the first posts about Turbo vent filter.
These FL1 TD4 engines turbochargers use vacuum to move the Variable Mozzles inside the Turbo, the vacuum is supplied from the vacuum pump on the passenger side of the engine, and its application to the turbo actuator is controlled by the ECU via a solenoid valve beside the filter. Either the water has damaged the solenoid valve, or pulled a vacuum hose off. They are ****ty little hoses made of perishable rubber and really ought to be replaced with non perishing silicone hoses.
My recommendation, check your intercooler hoses, check your vacuum lines, then test drive it. Regardless of it thefirst two things sort this issue, do a basic service, replace the vacuum hoses with silicone ones. If you still havent sorted the issue, then set about removing every plug from every sensor you can see and dowse plug and sensor with WD40 / similar. If that doesnt sort it I done know....
BTW If you enjoyed splashing in muddy puddles and want your landy to enjoy it too, waterproof the electrical connections with vaseline.