My apologies I guess I wasn’t as clear as I should’ve been in my previous reply; the only continuity to the O2 sensors from the pcm harness was to ground and C1-24.

C3-8/16 did not have continuity from the pcm connector to sensors 1/1 and 1/2 as it should’ve.

I’m also in the process of finishing up swapping the spark plugs to the stock copper ones to see if that’ll have an effect on the idle issue in the meantime.

 

How did you test??

 

I have a multimeter set to continuity, one end of a probe inserted into the PCM connector on the harness while it’s unplugged, and the other used to probe the metal connections on the inside of the plastic O2 sensor harness.

When I checked for voltage on the heater circuit last week I used the wire piercing probe to get a read on it while the vehicle was running.

 

Erm, Ok, I am seriously confused.....

Technically, three wires on the O2 sensor connector should have continuity to the PCM connector, that is the signal wire, from the PCM, the signal return, to the PCM, and the ground side of the heater circuit. But, you have to be sure you are actually testing the correct wire that you VOM is plugged into on the PCM side...... and you should ONLY have continuity on THAT wire. (I am assuming you are testing with the both the PCM, and the sensor, unplugged?)

 

I was testing with my multimeter per the attached photo, with both the PCM cables (C1, C2, C2) and the four sensors unplugged.

 

That's correct. Though, I would rather see resistance on some of them..... (the signal return wire, for instance.... as that value is IMPORTANT there.....)

And just for clarity: The PCM side is plugged into the wiring harness side of the connector, right?

If you have wires that do NOT have continuity between the connectors, then you have a problem in the wiring.... If you have multiple wires that don't have continuity, you should be getting a HOST of codes for that, not just one.......

 

Yes, the PCM side is plugged into the connector on the wiring harness that plugs into the PCM.

And yeah that’s what I’m thinking, it’s impossible to have the continuity be the way I tested and only have one code.

Also I got the new spark plugs in, no change to the rough idle and I have a pending P0135 code. I guess the only real option is to test again and somehow figure out why I’m not getting continuity but also no codes for the other sensor. I’m half considering just taking it in to someone whose worth their salt and just get this resolved.

 

Electrical can be oh so much fun.... One of my least favorite passtimes. But, when I was doin' it for a livin', I always got stuck with the weird ones.

 

Well I have a new development that might be contributing to my issue; I usually don’t drive with the vents/heater on but this morning I did since it was particularly chilly and I noticed I’m having a bit of the “wild vents” problem. Did a quick check of the vacuum lines and everything appears to be in operable condition and connected, I really doubt it’s my plenum since I have the Hughes plenum kit installed and as of two weeks ago there wasn’t any visible oil in the intake. One thing I’ve never checked is the vacuum/EVAP canister or the lines going to it; can that cause a vacuum leak or is it isolated since it’s after the purge solenoid?

I’ll have to do a little spritz with starter fluid to see where/if I have a leak.

 

Might just be bad check valves. EVAP system CAN cause a vacuum leak, but, that *should* set a code. Check the evap line going to the engine, see if there is evidence of the carbon canister blowing up.