Hi does any1 know what the problem is with my ford transit diesel engine?

I had a flashing glow light and i was lacking power so i changed the glow plugs and this didn't fix the fault what can be wrong with the engine? Its a 06 year ford transit tipper

The next time a light starts flashing you might want to look it up in the owners manual. And if you think the glow plugs were going to take care of power lose your over your head and need to take it in to the dealer for repair.

The glow plugs have nothing to do with power. They warm the cylinder to help easy starting… That's it