Oh were, Oh were does it go?

Gotta question. I have a 88 XJ, 4.0, automatic. Been having a rough idle lately during stops and a couple minutes after start-up. Did research on this forum and some others. I concluded I needed to check the IAC, grounding points, TPS, distributor etc. I put 1 can of seafoam in the gas tank, 1/2 can in the valve cover, and 1/2 can through the vacuum line. It ran good for about a week then started the rough idle again. So I cleaned the IAC and TB. While I was snooping around I noticed a two-pin connector just dangling. I checked the wiring diagram and it seems to be a connector for the engine speed sensor. The wire colors are violet/white and white/black. I cannot locate the place where this connection might go. Thanks in advance for the help. :repair:

Well, using a Haynes/Chilton by any chance?

Technically speaking, the CPS/CKP crank sensor is referred to as the speed sensor in the Renix FSM, however, if your crank sensor/speed sensor was disconnected the engine wouldn't run at all.

Now, there was a TSB modification to fix a problem with the crank/speed sensor to wire it with a more direct wiring harness to the ECU, and that is what was done to yours, as the wire colors just happen to be white with black tracer and violet with white tracer. So, just ignore that connector, it is not related to your issue.

When was your last tune up--cap, rotor, plugs, wires?

When was the o2 sensor last changes?

What injectors are you running?

Thanks Joe :yelclap: I changed the plugs last week but just looked at the cap and rotor, they seemed fine. I am going to change the O2 sensors in the near future. I have stock injectors, plan on changing those to orange tops sometime. To give you an heads-up, I am a mediocre do-it-yourselfer. I am using a Chilton manual for most of my repairs. When I changed my plugs, they all were gapped at .50 or more but looked good (no carbon build-up or damage). Thanks again.:worship:

There's no way they were gapped to .50! That's half an inch I think you missed a zero

I would pick up an FSM, they are worth their weight in gold. I have one for each of the years I own a vehicle from along with random other ones, every single time I buy a set I sit down and randomly page through it a bit to get a feel for what changed, random bits of info I may need in the future, etc. Every single time I have found something of relevance that I had forgotten I even wanted to know within a minute or two - the gas gauge resistance table for my 96, cruise control speeds on the 98, proper brake line routing and hookup on the 91, interesting info about how the valve bodies for the ABS and AW-4 auto trans work in my 92 books... you name it, if you want to know it about an XJ it's probably in the FSM somewhere.