91 Grand Prix won't start

[Apex]

My girlfriend and I just bought a '91 Grand Prix DOHC 5 speed for her to drive for a while. Went outside this morning to start it and it fired right up but died 5 seconds later. Now I can't get it to start again. It cranks over just fine but just never fires. The car has 170,000 but it had a newer motor (with about 100,000), along with new timing belt, water pump, alternator, and clutch put in 5k ago, also had the injectors removed, cleaned, and checked. Any ideas? It's has had a slight misfire at idle since we bought it but it's hardly even noticeable, and the fuel pump sounds great when you turn on the ignition. Any help would be greatly appreciated...

Forgot to mention, I live in MN and according to weather.com it's about -3° right now and it says it "feels like" -20°. But like I said it cranks over just fine it just doesn't fire up.

[MADz34-2]

I recently had some what of the same problem with my 93 lumina z-34.After letting it sit over night it wouldn't start,I would have to hold the pedal to the floor and keep cranking it til it would start..turned out to be plugs an wires.Ichanged them over the weekend and now it starts right up..

[Apex]

Well I just changed the plugs and wires a week ago.... Just checked the ECM codes...oh boy...where to begin...

Code 23
MANIFOLD AIR TEMP (MAT) or INTAKE AIR TEMP (IAT) CIRCUIT (LOW TEMP)

Code 34
MANIFOLD ABSOLUTE PRESSURE (MAP) SENSOR (VOLTAGE LOW-HIGH VACUUM)

Code 35
IDLE SPEED CONTROL (ISC) CIRCUIT

Code 42
ELECTRONIC SPARK TIMING (EST) CIRCUIT

Code 39??
Any one know what this one is?

Here's where I got the code descriptions from:

http://w-body.com/index2.html

Anyone know what code 39 is? Any ideas where to even start on this?

Checked one of the plugs and I do have spark...

[gpse3400]

I'm thinking the MAP sensor. Unless the DIS is malfunctioning, despite the fact you have spark. Have you tried modulating the gas pedal to coax it into starting?

[Apex]

I'm thinking the MAP sensor. Unless the DIS is malfunctioning, despite the fact you have spark. Have you tried modulating the gas pedal to coax it into starting?

Yes I've done pretty much everything possible with the gas pedal. I suppose I could swap the MAP...gotta love having 3 spare DOHC's

[JMo60]

is the vacuum connection to the map good? i have a feeling it is map related

[Apex]

If it was MAP related wouldn't it at least make an attempt to fire if not maybe even run just really bad?

[SappySE107]

ground or 5 volt reference (ecm?) is bad. Those are my guesses.

[Apex]

Just swapped the MAP sensor, no luck although I really have no idea if the sensor I have is any better since it's off a high mileage motor too.

[JMo60]

ground or 5 volt reference (ecm?) is bad. Those are my guesses.

yeah thats my guess too..

an engine with a bad map would most likely still start but not always. I didnt pay much attention to you exact symptoms,

[Apex]

ground or 5 volt reference (ecm?) is bad. Those are my guesses.

Are you talking about the 5 volt reference to the MAP sensor?

[Apex]

Just found a vacuum line that is not connected. I'm not sure where it goes but it appears to come up from the gas tank with the fuel lines and then sort of runs toward the firewall. I don't see any where it connects though.

[gpse3400]

that goes to the canister purge solenoid. look over by map sinde of the manifold towards the firewall you should see the soleniod there, has a red plug going into it. yeah just check to see if you map connector is putting out 5 volts on one of the prongs. If you swaped maps then I'm guesing the DIS is shot.

[Apex]

Would the MAP sensor be getting this reference with the ignition on or does the engine have to be cranking over?

[gpse3400]

key on