Rough Running/Missfiring

[Nick_08]

1989 325ix, M20 is running roughly and missing. Checked all vacuum lines, new plugs with confirmed spark to all of them, pulled/inspected injectors cleaned and re-installed also cleaned the plug under the intake. Resistance is up to spec on all of them and confirmed they are all working by holding screwdriver to injector and my ear.

What else?

Coolant temp sensor tested out good.
AFM tested out good but the temp sensor was at 5K ohms but it's 25* outside.
Also reset the ecu by unplugging the battery.
I will buy a fuel pressure tester tomorrow, the pump is confirmed to be working and fuel filter was changed about a month ago, there was pressure in the lines when I pulled the fuel rail.

when unplugging the spark plug boot from cylinder #2 and #5 nothing changes
__________________

[Aahj]

Turn the lights off, take a grounded screw driver and rub it over the spark plug wires...if you see them arcing...you have a problem. Had an issue similar to yours and the wires were my culprit. Got a great set of STI wires from Blunt Tech and it runs like a raped ape.

Aahj

[Nick_08]

That's what i was leaning towards on this. Just ordered a new set from them. We'll see what happens...

Anyone else have anything to share?

[Nick_08]

Update:

This morning I started the ix while it was stone cold. It sputtered to life and after about 5-10 seconds it ran perfectly normal. After the engine temp reached the 1/2 mark it began to sputter and miss intermittently and eventually was constant.

I wonder if there is moisture somewhere that froze and once thawed out caused the issue. Hopefully the new plug wires will show up today.

Anyone got input on this?

[Nick_08]

Cap was cracked. Thanks for the help guys...