When the engine is running watch the ignition coils for arcing on coil #3 of the four coil pack. The wire towers can crack releasing spark to ground even with a new boot covering it. Better yet remove the coil pack, clean it up and inspect it for cracks. Check the connections too, main plug and individual plugs to coils. They also do degrade. Best of luck.

 

Hey all, thought I join this thread to see if anyone has thoughts on my misfire issues.

My wife drove home the other day, called me and said our D1 1996 was running funny and the engine felt shaky. Upon her pulling into the driveway I could hear the inconsistent idling and it sounded like a misfire. I pulled the codes and got a P0307 and a P1313.

Initial tests I ran:

• Pulled plug 7 and it was wet (not oily)
• Checked for spark, and it seemed fine (blue spark)

I went ahead and replaced all plugs and wires as it seemed it was time, and cleared the codes. But nothing changed. Still a rough idle and the P0307 and P1313 came back.

I've checked vacuum lines and replaced the line from fuel pressure regulator to upper plenum as it was cracked — NO CHANGE

I've checked the compression on cylinder 7 with my hand, and I know this isn't the correct way, however, it felt violent and strong. — Should I still run a proper test?

I went ahead and pulled all the spark plugs again, and none of them seemed wet. Maybe slightly white?

I also tested my cylinder 7 fuel injector electrical. The voltage from the wiring harness and the resistance on the injector was good. I know this doesn't mean the fuel injector is spraying correctly, but I do smell fuel when I run the engine for more than 5 minutes. — Could it be that it is spraying, but not burning?

Last test I rand was unplugging cylinder 7 fuel injector while it was running. When I did this, there was no noticeable difference in the engine idle. But when I pulled the other fuel injectors I could notice a change in performance. — Does this mean that cylinder 7 fuel injector is the issue?

Each time I changed something, I cleared the codes and would drive it around the block. Codes or no codes, it does not run well and if I hit the throttle I can hear inconsistent pinging. P0307 always came back, but sometimes I would get a P1316 instead of a P1313. I

Any ideas?

 

I don't think we know enough yet to blame the injector. I think you did the right thing changing plugs and wires. The ignition coils are another possibility. Fortunately on your GEMS engine it's pretty easy to swap the coils around and see if the problem stays on #7.