One way to check for plug wires arcing is to just have the.engine running in the dark with the bonnet open and look for a light show.

 

Follow-up...I looked for any arcing between wires in the dark when running...didn't see anything. Since I thought this happened right after i went through the car wash, I replaced the coils next. Still no change. In fact, it's probably running a little worse. Starting to loose power and it's misfiring at load and not just rough at idle. Found out that previous owner relocated coils to the passenger side of where they normally were when I got a new set of plug wires and they were too short.

i have a fairly cheap code scanner and did find codes for misfires on 3 cylinders, and when I run it in live mode, it shows fuelsys1 & 2 faults off and on. I wasn't sure if a spark issue was causing misfires, then the fuelsys fault to occur, or maybe the other way around. I guess it would help if I fully understood how to read the live data in the scan tool.

So, is it looking like a fuel issue (stuck/plugged injectors, weak/clogged fuel pump) or am I missing any other electrical sensor? For a little more background (not sure if it relates), but one of the previous owners also installed a newer exhaust and removed the cats (both upstream & downstream O2 sensors are still in place and wired in).

 

Maybe check your fuel pressure and fuel pressure regulator. Do you use fuel injector cleaners?

 

I played this game a few months back. For me it was a combination of plugs and wires. I tried to go off recommendations off this board but ended up going OEM and problem solved. The price for the OEM wires hurts but you can get the OE plugs and Bosch coils from RockAuto. Not sure if the effects of COVID just turned aftermarket parts to garbage but I was sick of removing the upper intake troubleshooting and swapping parts.

 

I ran a couple of Chevron injector cleaner bottles but no difference that I could tell. I got the Bosch coils and was going to replace wires, but finally realized the OEM won't reach because the coils were relocated over to the passenger side. I had no idea they were originally mounted behind the intake.

Taking the injectors off now and will try cleaning them. It's worth a try and not too difficult

 

Yeah this one can be a real spicy meatball. I get a very slight stumble at idle every now and then. No codes and nothing to worry about, but of note.

Variables I’m looking at (many of which you have identified and are looking at or done):
- IACV (short list for me to clean)
- PCV modification (this cleaned up a lot of things and I think may have even stopped or at least slowed a couple minor oil leaks
- Vacuum leak (brake booster, intake, MAF, SAI stuff, etc)
- Coils, wires, and plugs
- Fuel system stuff

For me, I run a couple cans of Sea Foam every now and then in the tank. I also followed the specific procedure that’s around here somewhere in having a hose hooked up to the intake and let it suck out of a can of Sea Foam.

I know one coil was replaced prior to my purchase, but I don’t think it was new. Later this summer I’m planning on doing both with new ones and I think I’ll do plugs and wires at the same time. Since I did my water pump recently with a new belt, it runs ridiculously smoooooooooooooth. I’ll sort this last little stumble with the IACV I think and go from there.

 

Well, I bought a bulk roll of 8.5mm spark plug wire from Summit and made my own wires since the coils were relocated from their original spot. I still have a slight rough idle, but feels different than it was previously. I took the injectors out over the weekend and ran cleaner through them while hooked to 12v. After I reinstalled, definitely had more power again, but still the slight rough idle. Could one of them be dumping too much or too little fuel?

I think I've run through just about everything I can think of. Fell like it's better, but something is still a little off and causing a misfire/rough idle.

 

Have you sprayed some carb spray around the intake to check for a small vacuum leak?

 

An OBDII reader can check Long and Short Term Fuel Trims. They can help diagnose vacuum leaks, as well as leaky injectors.

Have you measured fuel pressure at idle? What about compression?