New member. 99 2.5l missfire #2
 

Aloha all!
Ive been wanting a straight four standard to the rear forever and I finally got! I bought this old pickup knowing about the missfire. I tested compression in the indicated #4 cylinder and tested against #3. Results good compression. So I did some searches and figured it was a bad coil pack, or ignition wires/plugs. Replaced coil pack, ignition wires, and plugs (without removing upper intake btw) but still bad. Needlessly to say i was depressed. Figured bad rings or valve guides on 1 or 2. After a 2 week slump I finally did a compression test on 2 and 1 ... good compression!!! Tested injectors and number 2 was bad!!! Replaced and now i got a strong 118k engine!!!! Riding cloud nine ever since. Figured id join the forum since I’ve been getting so much info here the past few months

Welcome to the forum and Good work

The dual spark plug setup gives better power, and also allows you to test spark plugs
The engine will run with only one set of spark plugs active, there is no alternating, wouldn't be much point in have 2 spark plugs in one cylinder unless BOTH fired at the same time, lol

Anyway you can unplug either coil pack and engine should start and run OK, not quite as much power but you are doing it to see if one of the 4 spark plugs might be misfiring, because you can't tell if one is until BOTH spark plug in a cylinder start to misfire, lol
So test it every now and then just because you can

Thx for the advice. I did unplug each coil pack while running to see if there were any bad plugs. All looks good. My next project is bleeding my brakes and clutch. Super dirty fluid + hawaii humidity. Prob never been done