Engine idling rough

I just bought this vehicle and the lot I bought it from said the only thing wrong with it was the rough idling, he said it's probably because it needs a tune up, which boy it did.
So I changed the oil, plugs and air filter and the rough idle is only slightly better. The weird thing is after you drive it for a while the rough idle goes away instantly, sometimes it comes back. I had the codes pulled and all it says is misfire bank #1, which I guess it means cylinder 1, it also brings up faulty 02 sensor, I did not change the plug wires but oh my gosh were the old plugs bad! It is amazing it ran at all with those in it. But anyway the wires did not look bad. I just hope to god this is not a fuel injector problem. Any ideas would be great, thanks.

There were three codes that came up before I changed the plugs.
P0301 P0171 P0201
I cannot see a date on the wires, but I was so sure the plugs were the problem. But there are the codes, hope this narrows it way down. Thanks.

So am I looking at a vacuum hose or could it be something much more major? Earlier when I drove it it smoothed out all of a sudden and I swear I could not feel it running, I hope whatever it is its quick and easy. I thought about getting some crc maf sensor cleaner and trying it but it's a long shot and it's $10.00 a can. What do you think I should try doing? Thanks for your reply.

On our 2003 Ford Explorer XLT we have been having a recent problem with a rough idle. But I also noticed that when we let off that accelerator that the RPM's drop down to an idle speed no matter what speed we are going. When we go at a slower speed and are coming to a stop I see the RPM's going down to about 400-500 and then back up. It start idling really rough and starts to stall out unless I give it some gas. When it does die, I turn it back on and sometimes it will die out again and sometimes it will start back up but start idling rough again.

I have been checking for vacuum leaks, but at this time have not found any.

Got ya, I might go ahead and replace both the hose and pcv valve since they are easy and inexpensive. But what about the p0201 cylinder 1 injector circuit malfunction? Is it something to worry about? Thanks.

Yes after clearing the codes it still has all three. It worries me because when I first start it of a morning the engine will shake violently once it is around 1000 rpm's, it also does it in over drive, I am scared it will damage the mounts if they are not already.

I have a ford explorer 2001 it started idling rough out of the blue it comes and goes only. I changed the plugs, plug wires. EGR, oil oil filter when put on the comp. It gave error codes for random misfires and each time on different cylinders, mech said there was nothing else he could think of that could be wrong Help what the heck could it be? The car runs good other than that and it only happens say 70 % of the time when you stop and its idle for more than a miute or two but sometimes runs so rough it almost dies you can touch the gas peddle and it lifts the idle and it stops for a minute or two then sometimes returns but sometimes it doesnt do it at all. I am at my wits end Help please? Dave.

Okay, so I did some more work on it, I replaced the PCV valve, grommet and the hose looked fine so I left it on, I cleaned the MAF sensor, somehow it had a tiny feather on the wire and got it off. I cleared the codes again, this time I took out the pcm fuse under the hood for a few minutes, I drove it again for about an hour, no change in performance, check engine light comes back on so I pull the codes again and only one came up, P0201 - cylinder 1 injector circuit malfunction. At least I got rid of two codes thought. So from here does it sound like a injector or injector harness? I also checked for vacuum leaks, the plug wires were checked and they are good. If this turns out to be an injector how hard would it be to replace? Thanks.

No I do not have anything like that, I actually would not know how to check it.