Q: ignition timing

Have a strange one here, started out as an intermittent shudder when hard accelerating. rotor button and dizzy cap had scene better days so swapped them out. didn't fix it and it progressively got worse. checked fuel filter absolutely chocked with crap. swapped it and cleaned fuel lines. got worse so had injectors cleaned and tested they where pretty bad but after a day in the bath tested fine. didn't fix it got worse get the car to 2500 revs and you can here it gurgling in the air intake checked valve timing belt a had scene better days was a little stretched so replaced didn't fix it, I've replaced leads plugs and coil. still no joy when ignition timing is set to factory settings it idles lovely but can't drive it without hearing the uni joints pinging from the buck and shudder if I advance the timing off the gauge to about 18 degrees btdc it still carries on but is more driveable there's no preignition rattles which is odd. thinking might be ignition control module?

My car has 130000 miles.
My car has a manual transmission.