320E misfire when warm!!

[Michael121]

Hi there would really appreciate the advice.

My 1993 w124 320E misfires very badly when up to full running temperature. runs totally fine on start up but as soon as it hits 80C it just instantly starts misfiring!
i feel im at my wits end trying to figure this out because i feel like ive read every forum thread and seen every video possible!
Parts ive replaced:

All 3 coil packs
all spark plugs
The wiring loom was replaced before i got it
water temperature sensor
ecu was swapped from another good car, no change
injectors were all rebuilt and calibrated

are there any pieces that might cause this? correct me if im wrong but ive read it might be:
OVP relay
crank sensor
purge valve??
fuel filter
fuel pressure regulator (when vacuum hose removed it doesnt leak so thats working correctly?)

somebody please send some knowledge to me because it is probably such a simple fix, but i just cant find it!

many thanks for help!!

Mike

 

[wrdcc01]

When it's mis firing spray freezer spray on each component, crank/cam sensor is a favourite as direct attachment to the engine and repeatable exact temperature failure.

 

[merc85]

Fuel Pump getting lazy when under pressure?

 

[d w124]

Ovp can as well as the throttle body.Also was the wiring loom replaced with a new one?

 

[Bayleaf]

Is it misfiring on one cylinder or more. If it's one do you know which one. Try swapping thing around eg coil packs even plugs. Bare in mind that new parts can be faulty. Good luck.