Pull your coils and check for corrosion that could be hurting spark performance, beyond that here are the definitions from the Lotus manual..
Misfire
P0300 Random/Multiple Cylinder Misfire Detected
P0301 Cylinder 1 Misfire Detected
P0302 Cylinder 2 Misfire Detected
P0303 Cylinder 3 Misfire Detected
P0304 Cylinder 4 Misfire Detected
Description
A misfiring cylinder can be detected by analysing crank speed variation. As a result of a combustion event there
will be a net acceleration of the crankshaft. Subsequent to a misfire event the engine will decelerate over the
period following the missed cylinder event.
Speed changes can be characterised by observing changes in the time period for a fixed angle of rotation after
firing events. A significant change in this period, assessed by comparison to previous periods, may be attributed
to misfire on a known cylinder.
Component connections
Connector Description ECU Pin ECU Connector
1 Supply Voltage Coil 1 Coil 2 Coil 3 Coil 4
2 Ignition Coil Feedback 22 22 22 22 52 Way
3 Coil Output (Logic) 52 26 47 48 52 Way
4 Ground
Malfunction Criteria
The operation of all the misfire codes is the same, the last digit relates to the misfire involved i.e. a code P0303
indicates there is a problem with coil number 3. P0300 indicates the misfire is random and not linked to one
particular cylinder.
Enable Criteria:
• Battery voltage between 10 – 16 V
• Coolant temperature between -10 – 120°C (14 – 248°F)
• Engine speed between 660 – 8010rpm
• Engine speed transient > 15rpm
• Altitude < 8000 ft (2438 m) / Baro > 756mbar
• Fuel level > 5 litres (1.3 US gallons)
• Engine load between 15 – 48% depending on engine speed
Disable Criteria: DFCO enabled (Deceleration Fuel Cut Off)
Monitor: Continuous
Limp home:
• Limit maximum engine speed to 6000 rpm
• Return the fuel system to open loop
• ECU may deactivate two cylinders, the misfiring cylinder and it’s matched other i.e. 1 & 4 or 2 & 3.
Potential failure modes:
• Injector related codes, as these can cause misfire codes to be set.
• VVT or VVL codes set
• Sensor connector and wiring for signs of corrosion or loose connections
• Spark plug / Cylinder compression
• Cam timing / Damage to rocker arm assembly
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Misfire P1301
P1302
P1301 Misfire level causing emissions increase
P1302 Misfire level causing catalyst system damage
Description
When the engine misfire reaches a high enough percentage the engine emission output levels can exceed the
allowed limits, this will produce the fault code P1301. If the misfire percentage is high enough and there is a
possibility that the catalyst may be damaged then code P1302 will be set.
See misfire faults P0300, P0301, P0302, P0303, P0304
Notes:
• The MIL will flash for a 1302 fault code
• The MIL will be illuminated if the 1301 fault is present for 2 consecutive trips.