147 1.6 misfire when cold.
I need your help.
Alfa 147 1.6 120hp started throwing up missfire fault codes when winter came. Using Fiat ECU Scan i get the following error codes:
P0300 - Misfires detected (generic)
P0302 - Cylinder 2 ignition failures
P0304 - Cylinder 4 ignition failures
P0301 - Cylinder 1 ignition failures
When starting from cold it runs fine for the whole warmup phase (the one with the raised idle). Then it starts to miss and has trouble keeping idle, but no error codes. Keep up the revs using the throttle and the misfire seems less and after about one minute it starts to run fine.
Also when starting from cold and start driving stright away it runs fine for the first like 300 meters then it starts to stutter and lose power and the engine light starts to flash. Keep going for another 2-300 meters and it starts to run fine again.
When using electric engine heater, which warms the cooling water for two hours in the morning, there is no misfire at all.
-Checked the sparkplugs and they look fine.
-Changed the complete ignition coil bracket (all coils + wires), measured the resistance in all eight coil packs (both the four old and the four that replaces the old...) and could not find anything strange. No change in engine behavior. Still misfire when starting from absolutely cold.
-Can't see anything wrong with my temperature guages either.
-Throttle body is clean.
-No water or oil in sparkplug holes.
What are your theories?
Pre heating of the lambdas faulty?
Crank positioning sensor?