My sister's 1992 Mitsubishi mighty max started jurking while she was driving the idling would go up in down in park she hasn't had a tune up in almost a year. So I did a tune up on her truck I change the oil & and oil filter, the spark plugs & spark plug wires, the distributor cap & rotar and the air filter. After all this it was still******** and seams to be miss firing. I checked the spark plug gapping it was fine and also the spark plug wire placement it to was ok. I thought I would check the plug compression also I belive the truck is fuel injected but am not sure where they are located. Please help thank you.
The******** and misfiring could be due to a fault with the ignition coils, get them checked.
Ignition Coil Resistance
Using a DVOM, measure primary coil resistance between positive and negative terminals of coil. See Fig. 4. Measure secondary coil resistance between coil positive terminal and ignition coil tower. Primary and secondary coil resistance should be within specification. See IGNITION COIL RESISTANCE table.
The surging is a fault with the idling system and can be due to vacuum leakages, high idling speed, lack of coolant in system, clogged coolant hoses to the ISC or a faulty ISC, (located under the throttle body).
Get the throttle body and ISC cleaned, readjust the idling speed and retest.
Did you try to retrieve for trouble codes?
IDLE SPEED CONTROL (ISC) MOTOR RESISTANCE TEST
Disconnect ISC motor connector. Connect ohmmeter between terminals No. 1 and 2 of ISC motor connector. If resistance is not 5-35 ohms at 68 F (20 C), replace ISC motor assembly.
1. Using a stethoscope, check operating sound of injector(s) during engine cranking or idling. If clicking sound is heard, injectors are okay. If clicking sound is not heard at each injector, go to step 2).
2. Disconnect injector electrical connector. Measure resistance between injector connector terminals. At 68 F (20 C), if resistance is not 13-16 ohms, replace injector.
3. If resistance is within specification, check injector wiring circuit for open or short to ground. If wiring circuit tests okay, replace injector.
February, 16, 2011 AT 9:39 PM
Hey thanks KHlow2008 I'll checkk all these out, hey I was curious about ignition coil suggestion on the first paragragh you refered to a figue 4 was the more images than the one below. Well thank you for help I appreciate your time and help it was needed.