L322 TD6 2003 Misfire/lumpy

Hello. I've got a 2003 TD6. When I start it from cold it's a bit lumpy and almost misfires, the engines shakes far too much. Once it's warm it's fine, and is for the rest of the day. My local garage tested the glow plugs and says 5 don't work. He doesn't want to get involved as he says they'll snap. I assumed glow plugs were only needed on very cold starts. But mine does start and run, albeit on about five cylinders, until temp gauge gets to normal. Then it seems fine, and drives lovely. Could anyone help please?

If 5 plugs are duff, I would get them replaced especially with winter approaching.
The glow plugs are really there to get the engine initially started, if 1 wasn't working and it wasn't firing on that cylinder it would only take a few seconds to start firing. (The TD5 only has 4 plugs, when it's very cold runs on 4 cyl for a few seconds then is back on 5cyl)
Sounds like you have more of an issue, has it been plugged into diagnostics?

Yes, was plugged in and no faults showed

I'd think about plugging it in elsewhere, as that fault should show.

The M57 should be a reasonable starter and run OK without the need for the glows....

It could be a temp sensor issue - if memory serves, the ECU defaults to a 'Up at Operating Temp' map if it doesn't get a plausible reading from the coolant temp sensor....then when it does get up to temp it runs fine....

I'd check the ECU temp sensor and the wiring thereto.