Truck Repair: N14 cummings Engine knocks and shakes on idle, long periods of time, battery cables

Question
Hi, my problem is that for more than 6 months my 99 volvo N14 cummings engine is been having a loud knock and shake in the engine block when on idle or when slowing down after a few hours of running it.This problem is intermittent.It stops when accelarating and speeding up. Also, it might stop or resume doing it for small or long periods of time for the rest of the day.Took it to the dealer and did not do it while there. However, they said it might be an electronic problem because there is no loss of power or smoke. So, they checked all injertors, wire harness for any wire short outs, battery cables for high or low
voltage, and replaced fuel solenoid. All good but no solution. Could it be the ECM,alternator, or EPS/TPS or temperature sensors because it's been doing sooner and more often since the weather is been hotter? Thank you.

Answer
I have NEVER heard of or seen an ECM causing that.And at $2500,I would not replace it.It is probably a bad injector,problem being having it do it to find which one is bad.Could monitor sensors to rule them out.TPS would cause problems other than what your problem is.EPS usually causes a no idle condition or no start.