Engine not starting due to cold weather

I have a 1998 GP with a 3.1, and this morning it wouldn't start. I've only had the car for about 2 weeks. It's about 0 degrees out, and I put Iso-Heet in the fuel about 30 minutes ago. It is turning over fine, and sounding like it wants to start, but won't. It has 157,000 miles, and seems to usually run great, except for the ignition wiring harness problem with the blower resistor only working on level 5, which I will be fixing this weekend. The car also seems to be shutting the whole electrical system down when I am jump starting it from another car. If I wiggle the jumper cables, the electronics blink and go on and off. Both battery cables are tight. Does anybody have any ideas?

Remove the cables and clean under them. You may also have bad cables resulting in the electrical system fluctuations you speak of. Even though the terminals are tight there may be a problem with the bolts that hold them in place. The other possible cause is a bad battery. Sometimes the battery terminals will break internally and cause such a problem. Take the battery out and replace it with another one. If everything works the problem is solved.

I cleaned up the cables and replaced the battery with a good one from my truck, and now the electrical problems seem to have gone away. The car still is turning over good and firing, but just not starting. It sounds like it's going to start all the time, but just isn't quite. I can't find a block heater cord, so I can't plug it in to get it warm. I have only run the car three times, one of which is when I just added 10 gallons of gas to the portion that the seller of the vehicle left in the tank. Do you think it could be bad gas left over from sitting for who knows how long? The car has run good every other time I've run it, but it has always been around 30 degrees at those times. It is now -2 degrees below 0, F, not celcius. Any other ideas would be greatly appreciated. The battery cleaning and replacing seemed to help a lot! Thanks.

I would put a bottle of gas line antifreeze in the tank preferrably Heet in the red bottle not the yellow one. If you don't have a block heater you can make one with a trouble light left burning under the hood at night. (Old poor man's trick.) You may also want to consider a slightly higher octane rating while the weather is cold. I don't know why but this usually will allow the car to start a little easier. If the tank is currently full add a bottle of octane booster to the tank. Good Luck!

It finally started. I put in a bottle of Iso-Heet, and it almost started. I put in a second bottle and it started and ran like crap, eventually dying. I put in a third can and now it runs like a charm. I also filled the tank with premium gas with the first can of heet. Theses bottles of heet are all the red colored ones, so hopefully I didn't overdo it. Thanks for all the help!

Hello;
Been following your situation and glad you got the correct advice and further glad for you that the Grand Prix is now working. I had a similar situation whereby it was also suggested (by Mechanic) to use Iso-Heet, the 1st attempt led the fuel to be examined whereby it was found to be gas tainted with 'water'...yes water. I had visited a friend out of Toronto into a local gas stn whereby I 1/2 filled the tank as I had previously heard of being weary of petro/fuel-from small locally run gas stns (not to slam them though, I find they are ordinarily very helpful)..nonetheless. the tank was drained, a 2nd Iso-Heet was added with fresh-petro/gas 1/2 tank and now she run's without any problems. Then and now.
Cool.
Mancini~