Again, try this simple voltage test to confirm your suspicions:
http://www.4crawler.com/4x4/CheapTricks/Starter.shtml#EasyTest

And it is likely something along these lines that may be the fix:
- http://www.4crawler.com/4x4/CheapTricks/Starter.shtml#OtherOptions

Sorry for no response, been a long week/post weekend. I pulled the ignition wire off the starter, cleaned it well, crimped it (after disconnecting of course <img src="/forums/images/graemlins/smile.gif" alt="" />) and as soon as I turned the key: click! So one simple solution ruled out. Next I'll check the ground wire (new, but maybe I didn't clean off the connection well enough), if that doesn't yeild any results I'll be testing the voltage coming from the ignition switch (as soon as I can get my other two hands to give me a hand). I'll probobly also just run a test jumper to see if that may be my problem. If all else fails I suppose I'll be pulling the starter out, which is sort of what I suspected but have been ignoring so far. Thanks for all the input everyone, helps out a lot.

Hmmm... i'm liking that option that is posted on Pirate 4x4. Might make that mod this wkend and see what develops. If there is still a problem, I'll just locate that momentary switch I hooked up into the cab and be done with it.

yeh, and you can hide that switch in plain view as a theft deterrent

Think I found the problem. Voltage from the ignition switch (at the starter) appears to be about 11.5 volts, battery voltage of 12.23. I'm suspecting that this is the weak link sometimes dropping even lower, although it doesn't really explain the temperature affect (lower temp, lower resistance, meaning it should start better when cold?). Either way, a relay can't hurt anything, and is inexpensive so I'll be doing that today and we'll see if that fixes anything.

Battery voltage is lower when cold and especially if the vehicle has been sitting overnight. Adding a relay works by bypassing the stock wiring and feeding battery voltage directly to the starter solenoid with minimal voltage drops.

So on my adventure around town today I found that nobody had a relay to my likeing for this little addition. On a whim I stopped by the dealer, who I've found to be generally pretty knowledgable and helpfull. Talking to one of the guys in the parts/service dept. he seemed to think that the voltage at the energizer wire wasn't critical, saying that even down to 10.5 volts should activate the starter. His suggestion was that the contacts on the starter may be just close enough to the outer limits of the tolerance that the temperature affects a good contact, which could be the case, though I'm skeptical for several reasons.

1) Doing the same thing on a 40 degree day that it did on a 90 degree day and if the tolerances are really that close I'd expect it to give me more trouble on a cold day.

2)After it starts cranking (after several clicks), even if it was half a revolution, it will crank reliably the next time I try.

3)There is definitely a load on the system when it clicks, though I haven't tested how much yet, I need to hook up the multimeter properly to see what is going on for sure. Basicially if you try to start the truck without the clutch in or the safety cancel, the voltmeter lowers a tiny bit, but in this case with the safety cancel engaged, it drops significantly.

Of course, one potential answer to the second point could be that the contact and flow of energy through the contacts is heating it up enough to bring the clearance back within spec if it really is just barely off.

At this point I see no reason not to put in a relay anyway, can't hurt, so I'll probobly do that when I can find a good one. If it continues after putting in a relay I would suspect the starter, which luckily I can get a brand new OEM one for $114 if it comes to that.

The FSM lists a 0.5 volt drop (from the battery) as the test for good voltage at the solenoid. Yes, it'll pull in lower than that but you need to realize that once it does pull in and send 100s of amps to the starter motor is that the battery voltage will drop lower. So if you are at the lower limit of pulling in the starter solenoid then it may drop out once the contacts close and send current to the motor.

Solenoid does pull about 20 amps per my measurement. So that is about like turning all your lights on and off.

I found a good relay I had laying around (one good thing about having an audi, you have lots of spare parts laying around). Mounted it in the relay/power distribution box and viola! starter on the first try. So far so good, but of course the only true test will be wait and see since it was an intermittent problem to begin with. I am optimistic however.

There's an 88 4R being parted out right now in the FS section m'man. <img src="/forums/images/graemlins/cheers.gif" alt="" />