I would suggest verifying the connectors to the coils are both black and the connector to IAC (see picture in above post) is gray.

Your symptoms are similar to how I learned the hard way the IAC and coil connector are both the same fit but are at least different colors. The IAC connector will reach the drivers side coil.

2003 Discovery 128K with high miles service complete.

 

Yep Ive got the IAC on the correct fitting. I'm going to pull the upper intake off tomorrow and check that the injectors are all in the correct place. I'll also check for additional wiring i may have missed.

 

Okay so Ive taken the upper intake off to check the injectors and everything else in there. 2 Things I noticed: 1. The upper intake bolts were not on as tight as i thought they were, it didn't take much to loosen them. 2. The driver side EGR valve was a little lose on the SAI pipes. I didn't notice because the tubing and hoses made it all appear tight when it was all put together. I've checked my wiring and everything appears to be in place. Though I noticed that one of the back injectors was turned to the side where all of the other were at an angle... I never removed the injectors for this job. Do you put injectors in by screwing them in, perhaps this one was lose?

Could either of these cause a misfire/stall?

 

The injectors are held down by the fuel rail, the sealing is by an "o" ring top and bottom on the injector so they can turn (within limits of the electrical connector of course) If your upper intake bolts were loose you may not have had a good seal which would have given you a big vacuum leak. Make sure you use a new gasket, those are a 1 use gasket, once they are tightened down, they crush and can't be used again. If you have a vacuum leak, it won't idle worth a damn (if at all).

 

Ah damn I didn't know they were 1 time gaskets. Sounds like that could be it..

 

I wouldn't go as far as to say the upper intake bolts were lose, but they only took one halfassed push with a wrench to loosen. Still sounds like this is the problem(hopefully anyway).

 

I've had to be away from the truck for a few days. But I was wondering could it also be possible that my spark plug wires have been damaged from pulling them?

 

It's possible, depends on the wire and how you pulled them. If you pulled them by the boots at the plugs I would say "probably not", but if you grabbed the wires themselves and pulled, then it's possible/probable. A miss on one cylinder probably wouldn't cause it to die.

 

do you have spark? you can get one of those cheap plug tester for like $5. Do not ground the wire or plug to the engine you can toast the ECU.
also i have reused my upper gasket several times now.

 

Just did some digging and I found that there is a washer attached to the wiring harness down the back of the drivers side head. there is a hole in the head for a bolt to go through the washer. Is this meant to serve as a ground?