I recently replaced the spark plugs and the distributor cap and rotary. I felt the car was misfiring, it would idle very rough and randomly lose power accelerating. I'm wanting to sell it so I'm trying to get it running as well as I can. So when taking out the plug in cylinder 4 it had oil on it, but no other cylinders had oil. Then I replace all 4 plugs and the car runs fine for a day, smoother idle and better acceleration.

Then it started doing the same thing, only worse, and much more randomly. I take it auto zone to use the scanner and he told me all 4 cylinders are misfiring. HE suggests I replace the distributor cap and rotary and double check that all the plugs are connected and in the right order, the plugs are clean even the one in cylinder 4 that had oil is spotless when I check it. I bought and replaced the distributor cap and double and triple checked that all the wires coming from the cylinder to the distributor cap are in correct firing order, which if Im not wrong is 1-3-4-2 and the cylinders are numbered 1-4 starting on the opposite end of the distributor cap so right to left when facing the car.

After doing that it runs better again for a few hours but I decide to get it checked again and the scanner comes back with the same problem, all cylinders misfiring at random. So I buy my own OBD2 sensor so I can try to correct it myself, but now the OBD2 sensor I bought wont work. Auto ZOne guy cant connect his either, It will come on and read if I manually hold it at the port, but I cant get it to stay connected long enough to get a read. I checked the fuses, I think the OBD2 sensor and cig lighter are same fuse, or thats what my google fu got me anyway, and it was good. I replaced it anyway since I had a spare, and that didnt do anything to help.

So I'm not that good with cars and now with the OBD2 sensor going out I'm kind of at a loss at what to do. I cant get it to stop misfiring and I feel like replacing random parts until my car runs right isnt the best idea. If anyone has some advice I would appreciate it. I think its some kind of ignition problem, but my car knowledge is limited to what I can get from google and the dude at auto zone so I could be way off. I think the OBD2 sensor is a wiring problem but I dont know how sensitive that piece is, it might be a single bent pin I could bend back. I feel like changing spark plugs should be the very least I could do myself before trying a mechanic and getting ripped off.

All wires are in the correct spot and are on snug and I have them neat not running over each other, I made sure not to overtighten the plugs as well, so I dont understand what I'm missing.

Any advice at all is appreciated.