Sorry for the randomness of this, but it's 2am and it's been a LONG day.

I have a 2003 Pontiac Grand Am GT, 3400 engine, that sometimes starts, most of the time doesn't. We had an overheat issue due to a bad (intake or head) gasket back in August and stopped driving it. Since then we have replaced a few things. The mass airflow sensor is bad (unplugging while car runs should kill it, but it doesn't do anything). I was told that if that was the cause of it not starting that just unplugging it until it is replaced would let it start. After being stuck at work and making my wife come get me at 11pm with our 2 year old that had just fell asleep, I can assure you that is not the only cause. When we had the overheat, we had codes for misfire on cylinder 1, O2 sensor bank 1 sensor 1 overvoltage, and bank 1 sensor 2 low. We drained and refilled the coolant, replaced the thermostat and it was working. However, it would randomly not start, but we figured it was just the cold (-30+ windchills for a week) and would just wait until we got our taxes back and fix the gasket/etc when it was warmer.

We have not had the gasket fixed yet because it still doesn't start consistently. We had the Snapshot device from Progressive in when we were not using it and the battery died, so we replaced that. Since then we have replaced the fuel pressure regulator which that and the battery being 100% dead and out for a few days cleared the codes (was told a bad regulator is a common cause of those codes). But it still doesn't start all the time. Some days it starts and you can run errands all over and turn it off 5, 6, 7 times during the day with no issues. Other times it will not start at all. When it does start, there is no hesitation or problems at all, it starts right up. We are at a loss as the cause. The fuel pump runs when you turn the key, there are no lights on the dash when it does run, the air filter is a little dirty, but it was replaced about a month before we stopped using it so it's still good. We do not have anywhere near enough money to take it to a shop and tell them to figure it out because they will just start finding all these other issues and charge us for them when we can do those ourselves after we get it running. (drive belt, pulleys, harmonic, etc are starting to squeal and need to be replaced, and a small hairline crack in the top of the coolant surge tank but no coolant leak). My father in law does most of our repairs himself since he worked in a shop for countless years and currently works as a supervisor at Cummins. We don't really want to start tearing everything apart and replacing things just because they are starting to get to the end of their life, so any ideas?

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