Engine Misfire
 

I have a 99 GT My car is missing and is blowing out a gray blueish smoke #3 cylinder has black on it and #4 has gas on it like the injectors are full streming. whats wierd is when I unplug the mass air the idle gets better. I have looked at the pistons 3 and 4 and they are very clean like they have been washed with gas. I am not shure if the mass air would do this. I was messing with it yesterday and I unpluged the battery then I drove it around but now I cant get it to though a code. and its running horrible.

The pistons may be washed with coolant,sounds like a blown headgasket symptoms with the rough running,wash and smoke from tail pipe. I would recommend performing a compression test with cylinder leakdown tests and also checking cooling system for any traces of hydrocarbons in coolant,this test requires a tester that is placed over the coolant resevoir with cap off and there is a fluid in the tester that will change color if hydrocarbons are present in cooling system. A cooling system pressure test doesnt always detect any internal leakage. You may want to call a ford dealer and ask the svc dept if they have seen what you are experiencing? If your lucky they may have seen this before and be honest and tell you,most likely they will want you to make a appointment. Good luck and let us know what is wrong when fiqured out.

Misfire
 

I smell Gas on the plugs so i dont think that it was a head gasket. I think it is an injector problem or a computer problem.

Problem found
 

Cylinder #4 has no compression what I belive happend was a valve spring broke. so be where the valve springs are weak.

I'm sorry to hear about your misfortune. sometimes a compression test can get to the bottom of a bad misfire or driveability problem. Good luck with your repairs.