Quite the starting problem...

[pissedabouteverything]

Over the last year, our 2001 Chevrolet Malibu with a 3.1v6 has become increasingly difficult to start to not starting at all. It first started with occurences of once a month where the car would not start after being driven. At first, unplugging the MAF sensor would magically allow the car to start. We replaced the MAF sensor and the problem went away, for a few months. Then it began again, but more frequently this time. I tore out the ignition switch and discovered that the terminals inside were pitted and burned. I replaced the ignition switch and again, the problem went away for a few months. Now it's back, and I am lost, asking for help.

It happens after the car has been driven, and refuses to start back up unless allowed to cool for 4+ hours now. It has spark, and the fuel pump is working. When you go to start it and it's acting up, there is fuel pressure and you can hear the pump in the tank do it's fuel pressure check. If you put starting fluid into the throttle body (away from the MAF) the engine will start and run until the fuel source depletes, in this case the starting fluid.

The theft light turns on as a bulb check, then off as normal when this happens, leading me to beleive that the theft system isn't the culprit, but I would be proven wrong.

Things done in the past year:

Had a real mechanic replace intake manifold gaskets, they were leaking coolant for a year or so, this starting problem wasn't occuring until a few months after.

Spark plugs+wires.

Battery changed.

Checked for lose/unplugged wires/harnesses visible in the engine bay.

No codes and no check engine light. Gas milage is also decreasing greatly. When the car finally does start, the exhaust smells like it's burning REALLY rich, but has no signs of flooding. Also, the key can be removed from the ignition while the engine is running, but the car doesn't seem to think it's being stolen.

Any suggestions are appreciated. We want our car back, and we don't have money to be towed, so we are stranded at places until it decides to start up.

[DrivenDaily]

Not sure if this helps, but I had a '90-sumthin' Cavalier that would start cold and was intermittent when hot.

Turns out it was the $15 crank sensor under the engine that was loose. I had already bought the new one so I just replaced it, but I'd have bet ya that had I simply re-tightened the original one the engine would have started and run as it should.

[pissedabouteverything]

Originally Posted by DrivenDaily

Not sure if this helps, but I had a '90-sumthin' Cavalier that would start cold and was intermittent when hot.

Turns out it was the $15 crank sensor under the engine that was loose. I had already bought the new one so I just replaced it, but I'd have bet ya that had I simply re-tightened the original one the engine would have started and run as it should.

Ah, that is a brilliant idea! How do I find the sensor? I'm afraid I have no idea what it looks like so I cannot go searching for it on the block. Also, is there a way to test and confirm? Thanks!