My 2004 Pontiac Montana had the service engine soon light come on. It then took 2 times of turning the key for the van to start. Then two days later I went to leave work and it wouldn't start at all. Just sat there turning over very quickly. Goodyear had it all day and can not figure out why it isn't running. All their tests and equipment says it should be running. It is not. Had the crank shaft sensor wire replaced a year ago when the same thing happened. Goodyear says that is not the problem. HELP!

SOURCE: 1999 pontiac grand prix . will not run

If wiggling the wires cured the code, then one of the wires is broken inside the insulation. Pull on each wire one at a time. look for the colored insulation to stretch, this will be the broken wire. For the other car that wont rev up, this is a common when the catalytic concverter is plugged up. This will also cause MAF codes, and in turn, TRAC OFF light.
See http://www.greatautohelp.com

SOURCE: at times cranks and runs fine other times it will not crank

Hello edspring1...the little key chip you mentioned is the onboard security system for your firebird...GM called it the VAT system..it's possible this could be the cause of the no start conditions, sometimes they will reset if you disconnect the negative battery cable for 30 mins.
I really dont think that is your problem though...under the steering pillar...there is a "slider" type ignition switch...meaning...the terminals slide togather to make contact when the key is turned...these darn things get worn to a point they start arching and eventually wont make contact at all...i replaced one last week on a 95 firebird that had the same problem you are describing now.
i'll post a pic of the slider set in position for a tilt steering and non-tilt column....note the difference.
Good luck...i hope this helps...please rate me a fixya.

SOURCE: 2006 Pontiac Montana wont start after replacing

Sounds like your starter solenoid is stuck in the on position if you can get down there and have some one hook the battery on, hit the starter with a hammer some time this will disengage the starter.

SOURCE: head lamp wont work

Try replacing bulbs they could have both gone at the same time,I think it takes a 9006 bulb. You could check by pluging low beam plug into high beam bulb if it works the low beam bulbs are gone

SOURCE: I have a 98 Pontiac

When you replace the ECM , there is 1 in 1000 chance that you don't have to have it reprogrammed to your car. Problem is probably in the security. As you said you have no fuel and this is what the security shuts down. Some auto parts stores are reprogramming for way less than the dealer.