94 rodeo black smoke and shuddering problem

I have a 94 Rodeo V6. I am not sure which engine it has in it a 3.1 or 3.2 to be honest. I changed the oil this afternoon and used mobil synthetic blend for high mileage vehicles. Anyway, a couple hours after i changed the oil I left to go to work. I noticed that the car idles very rough now and I am getting black smoke from the exhaust tip. To further complicate things I get on the road and as long as I don't push the gas past 1/3 it seems to run fine but when I push the gas further the car bogs down and shudders kind of jerks violently. As soon as I let up on the accelerator it goes right back to running smooth. transmission seems to be shifting okay and everything. Anyone have any ideas? Our visit to see family is at risk if I can not get this fixed within the next day or two without spending a fortune. i am hoping it wont be a horrficly expensive fix. Thanks

Elementary question...
Oil level checks out?

Also, how are the plugs and other ignition components?

This one just happened to me. White smoke out of the exhaust is an oil problem so don't worry. Black smoke out of the exhaust is a gas/air problem. I had the exact same problems as you and I took it in and they replaced the plugs/wires. This didnt really help that much so I took it back in and they replaced the O2 sensor and it runs great. Try the oxygen sensor first.

Sounds to me like since you just got an oil change and you used the high mileage oil, which is a little thinner for older engines. This oil really is great but sometimes it creates oil leaks because it is thinner. These arent a big deal and dont need immediate replacement but they do affect the engine otherwise. The oil leak can cause things like the 02 sensor to prematurely go out. Happened to me.

Good luck!

I was gona say souds like o2 sensor but have it checked out because if I am not mistaken an OE for yours is around $300

i replaced my y pipe and cat a week ago, and the old one was so rusted into the pipe i couldnt get it off, so i went to autozone and got a new o2 sensor for 22 dollars, i dont know if yours is any different but it worked for me

I had a shop check it out. The MAP sensor came in out of range and I had thm repace it. It ran fine for two thousand miles. The mechanic cleaned the plugs and put them back in (they were covered in dark black soot). Now today for whatever reason it is exhibiting the same symptoms but with a twist the CHECK ENGINE light is on. Now to answer everyones questions.

1) Oil level and pressure are okay.

2) Plugs were covered in unburned fuel and soot wires look okay

Soooooo I am going to take it back in today out here and see what they tell me. I hate pep boys but I wanted a national warranty. Soo back to them it goes and maybe they wont charge me a rediagnose fee since it is the exact same symptoms.