Why am i running rich occasionally

[Synned]

1.) Problem only happens when the engine is warm/hot.
2.) Car idles OK
3.) When the problem is happening I have seen black smoke out of the tailpipes.
4.) Engine backfires when revved. (While the problem is happening)
5.) Misses or hesitates in the lower rpm range.
6.) ECT, ACT, plugs, wires, dizzy cap & rotor have been changed. MAF has been cleaned.


So basically this happens when the car heats up. It starts hesitating and I'm pretty sure running rich as well. On a cool night or when I first start the car it runs amazing. Timing is at 10. Car is freaking stock!!! What is wrong?

 

[Synned]

Ugh,
Fuel pressure is checked, 32 at idle, when wot its like 40. Vacuum is good. Car still bogs/hesitates when you get on it after it has heated up. I went to a friends garage and the guy there couldn't figure it out either. He thinks it might be clogged cats. I'm at a complete loss. I just ran a can of seafoam through it and there was a ****load of smoke but I guess thats normal. He called a ford dealership and the guy that hes friends with at the ford place is going to search their database for this known problem and get back to me. Do our catalytic converters get clogged? I guess nobody really knows since nobody leaves them on . Jrickter, fuel, vaccum, and tps are all good. TPS was check with a snap on which also verified the o2's and maf working within range. The computer shows nothing. Cylinder balance test shows nothing.
When I ran seafom, the right exhaust pipe smoked a whole lot more than the left one. The same side in which one of the plugs looked oily. Coincidence?
It doesn't sound like an ignition problem does it? TFI/PIP?

You guys are my last hope!
Joe

 

[mo_dingo]

If the car runs perfect when it's cold, but poorly when it's hot, you have some bad O2's, or your HG is blown. Or you have a valvetrain/piston right problem.

But start w/ the o2's and go from there.

But here is another tip. Once the car is warm, get in 4th gear at 35mph, and put the pedal all the way to the floor all the way to 90 or so. If the problem is gone, your O2's are your likely culprit. Since the motor is warm, and you put it to WOT, that brings the maf/ect/iat sensors online and uses them and if it runs ok then that only leaves the O2's. But you should make sure the heating wire is getting 12V for each O2 before you comdemn them.
Scott

 

[Synned]

If the car runs perfect when it's cold, but poorly when it's hot, you have some bad O2's, or your HG is blown. Or you have a valvetrain/piston right problem.

But start w/ the o2's and go from there.

But here is another tip. Once the car is warm, get in 4th gear at 35mph, and put the pedal all the way to the floor all the way to 90 or so. If the problem is gone, your O2's are your likely culprit. Since the motor is warm, and you put it to WOT, that brings the maf/ect/iat sensors online and uses them and if it runs ok then that only leaves the O2's. But you should make sure the heating wire is getting 12V for each O2 before you comdemn them.
Scott

Well I'm almost positive it isn't a blown head gasket. The oil looks fine and I don't see smoke. I tried running the car without the MAF and got nowhere. The ECT is new, and I tried a new ACT and it didnt do anything. I guess the only thing to check is the right voltage going to the o2's.