Been having problems with my 99 expedition for about two weeks now. It's been stalling, cutting off, and emitting black smoke from the tailpipe. I've gotten a t-valve put on and a tps sensor problem still persists. Does anyone think that it could be the catalytic converters?

 

I'm not sure what this "t-valve" is?

Is the PCM throwing any codes?

 

yes,
I think it was showing codes for more that one thing. One of them was definitely the tps sensor. My boyfriend let his cousin run the check on it. I think one of the codes were for the converter also. I'm definitely thinking of buying me one of those code gadgets myself. I saw one for ford vehicles for 30.00 at o'reilly's. I can't explain what the t-valve is, but it was burned out. I had to go get it from the dealership, because thaey don't sell them at the part stores. My next route will be to replace the converters. my number 3 spark plug is stuck and needs to come out. I read that a foul plug can make the converter mess up. I also rode around for a long time with my #4 plug missing, because it was stuck also. Maybe this has caught up with me.