'96 sat for 2 weeks, now hard to start

[lesabre400]

Ok, from what I've found on a search, this could just be too low voltage getting to the fuel pump, but here's the problem:
It's a 96 XJ Country w/ 4.0 auto (157,000 km) on a dealer's lot. Went to drive it tonight and the battery was dead-flat - truck had been sitting for about 2 weeks (there seems to be a bad ground in the headlight circuit because they come on whether you want them to or not). Jumped it with another vehicle, cranking sounded good but wouldn't start unless you held the throttle down a bit. Take your foot off and it would die instantly. The dealer said he had the same problem with it the last time they tried to start it (that day or the day before). He said after 15 minutes of holding the throttle at 1100-1200 rpm, it would idle without stalling and ran fine. I'll be putting that to the test when I go back. Hopefully 15 minutes of high idle charges the battery enough to supply the required juice to the fuel pump. Or is it temperature related? Once things warm up the problem goes away? Or have I been working on carburetors for too long? Any other ideas?

[johnnyc]

Get them to replace the battery. A battery with a bad cell will not allow the computer to "remember" the idle. When you keep the idle up with the throttle, the computer is "learning" the idle. I had this exact same problem, and a new battery solved it.

Don't know about the headlights though.

[8Mud]

Sounds like the IAC is sticking, start it up and spray some good penetrating oil into the IAC orifice with the motor running and working the throttle by hand a bit. After taking the sound box off of the throttle body, you can see the IAC opening (orifice) inside the TB bore on the passengers side of the bore (kind of a rectangular opening). The plastic guides under the sound box break off easy so be carefull.
If this doesn't get it working right again, you may have to remove the IAC and clean everything out that way. Sometimes the IAC itself needs replacing, but not often.
The headlights staying on, could be a bad headlight courtesy timer or maybe a bad headlight switch.
If you turn the key off before turning the headlights off, then turn the headlights off, the headlights stay on for about 30 seconds or so (headlight courtesy timer). Supposed to give you time to get to the front door of the house or out of the garage, whatever.
If the timer is bad, it may keep the headlights on continously.
The headlight switches have a tendancy to self destruct on occasion, no telling what is going to short out or which fuses are gonna blow.

Like XJOJNNYC said, low voltage can give the IAC grief trying to position itself, a little oil or other crud in the IAC adds to the problem. Sometimes jumping a discharged battery, the battery sucks so much juice, that it starves other functions.
Be carefull jumping an OBD vehicle, I've seen and heard of this causing strange and wacky failures. The computer sometimes tries to reprogram itself, the voltage regulator will crap out and you'll end up with a no charge condition or worse.
Getting the jumper cables on backwords can kill a computer, voltage surges are always dangerous. I've jumped them before, but I always try to recharge the battery on the battery charger, when possible or swap in another battery.
They have burnt up a ton of computers at the sea ports here in Germany. The batteries would go dead on the voyage and the guys at the docks would jump them off with a giant truck battery on a dolly. They are used to European vehicle batteries, which have the battery poles on the opposite sides.

[lesabre400]

Thanks guys - talked to my mechanic and he had the same suggestions. Sounds like the computer just needs to relearn after being shutdown. The headlight thing could be the DRL module or the courtesy timer. I'll be taking the truck to him tomorrow, so we'll see what he finds. When I bring up all these "problems" with the dealer, I should be able to get a good deal.