Sounds like classic bad GPs to me. I've never had luck checking the resistance of the GPs I always pull them out and give them 12v. If they glow bright orange then they are good, if they don't then they are bad. Don't touch the GP while you're doing this, they get REALLY REALLY hot.

Also when it starts getting cold you should let the GP run longer than the light is on. The light is just an idiot light. The GPs stay on for about 30sec after the light goes out. If you listen you can hear the relay kick off. Let it run through the full cycle then turn the key. But at any rate you shouldn't have to be glowing the full cycle when it's 50*F outside which make me think its a bad GP or two.

You could also have an air leak in the fuel system. Before you start the car on a cold start, look at the primary filter and see if there it a big air bubble, or if it has the normal little air bubble. If you have a large portion of the primary filter with air, then you've got an air leak.

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