1996 Mitsubishi Eclipse code 300 multiple misfire

STARFISHROBERT

MEMBER
1996 MITSUBISHI ECLIPSE
4 CYL
FWD
MANUAL
88,000 MILES

Was driven down the road, car started boggin out. Made it home but couldn't give it much gas or would stall. Pulled a 300 code(multiple misfiring). Changed plugs, wires, coil(distributer), ignition switch, still wont run. Gettin gas out of relief valve. CEL blinked 1 time then 2 times then 5 times then 5 times again.

1 Reply

KHLOW2008

MECHANIC
41,815 POSTS

Hi starfishrobert,

Thank you for the donation.

Here are the description and trouble shooting procedures.

DTC P0300 - RANDOM MISFIRE DETECTED

1. Connect external tachometer. Using scan tool in MUT II mode, read SERVICE DATA No. 22 (crankshaft position). Check engine RPM during cranking and at idle. If RPM displayed on scan tool and tachometer are equal, go to next step. If RPM displayed on scan tool and tachometer are not equal, go to step 4).

2. Using oscilloscope, perform crankshaft position sensor wave form check. Connect Test Harness MD998478 between Crankshaft Position (CKP) sensor and harness connector. Connect analyzer special patterns pickup to CKP sensor terminal No. 2. If test harness is not available, connect analyzer special patterns pickup to PCM terminal No. 89 (Blue/White
wire) Go to next step.

3. With engine idle speed stable, compare CKP sensor wave pattern to standard wave pattern. If wave pattern is okay, go to step 5). If wave pattern is not okay, go to next step.

4. Check CKP sensor connector, PCM connector and wiring harness between PCM and CKP sensor connector. Check CKP sensor and sensing plate for proper installation. If wiring, connectors and sensor installation are okay, replace CKP sensor.

5. Start and warm engine. Turn all accessories off. Increase engine speed to 2500 RPM. Using scan tool in MUT II mode, read SERVICE DATA No. 81 (long-term fuel compensation). If fuel trim is -12.5-12.5 percent (during closed loop), go to next step. If fuel trim is not as specified, check fuel trim fault.

6. Using scan tool in MUT II mode, read SERVICE DATA No. 21 (engine coolant temperature). If temperature displayed on scan tool is equal to actual Engine Coolant Temperature (ECT), go to next step. If temperature displayed on scan tool is not equal to
actual ECT, check ECT circuit.

7. Check ignition coil, spark plugs, spark plug wires and compression pressure.