Every time I turn my A/C on my truck the RPM goes up and down

I work with a Deputy that has a 2005 f-150 5.4 triton v-8 xlt 4wd and is having a problem with his truck shutting off when the wheel is turned all the way to the right and it also done it to him when he stopped immediately. When his truck idles the rpms fluctuate up and down.

I'm having the same problem after changing out the battery. My mechanic said he needs to download the new codes to the computer. I didn't try replacing the battery cables in the reverse order. Will try that.

I believe that year has a idle control sensor. I would guess that is his problem.

I am hoping someone with vehicle mechanical knowledge can give me some help. I do not know much but am trying to learn. We are on a limited budget so the more repairs I can do myself, the better. My brother knows a good deal about auto repair but he lives about 4 hours from me.

The problem I am having is this. I have a 2003 Ford F-150 V6 manual 2 wheel drive pick-up. When I first start the truck, the idle will go up and down. I think when the idle is steady, it holds at about 1000 rpms. When it revs up and down, it will go a little below 1000 rpm and back up, over and over. When I am driving, I do not notice anything. Once the engine warms up, I think the problem goes away. I can not remember for sure now, but I think this only happens during cold weather. During the summer when the temp was 90+, I do not think it did this. My service engine light is on. This past weekend, we went to see my mother and brother. We went to an AutoZone and they checked the codes. I think there were three codes that showed up. Basically, I was told that it said that my truck was running "lean" (which my brother tried to explain the meaning to me). I was told that the most likely culprit based on the codes and the possible causes given on the print out was that the Bank 1 O2 sensor was bad. One of the possible causes given was a vacuum leak. However, my brother and the person at AutoZone said that if that was the issue, that I should notice more problems than I do. We replaced the O2 sensor. I turned off my check engine light (I disconnected the positive battery cable and turned the key with the clutched pressed - as if trying to start the truck - this will turn off my check engine light). At first, it seemed like this may have helped. The rpms at first seemed as if it was about to do the same thing, but then did not. It may have revved up slightly for a very short duration and then stopped. The next day, when we drove home, however, the same thing started happening again and the light came back on.

I went to another AutoZone and they read the codes again. This time I was told that it was showing the bank 1 and bank 2 O2 sensors. It gave similar possible causes as before. Except this time, the way the person explained it, I am not sure if he said that my truck was running too lean or too rich or sometimes both. He asked what kind of gas I had been running. I told him 87 octane. He said that now that gas has 10% ethanol, that 87 octane is not good for my vehicle and is causing the problem. He also said that it could be that the MAF sensor needs cleaning. After checking my engine, he discovered that I do not have a MAF sensor (to his surprise). He told me to get some MAF cleaner, showed me a plastic tubing piece to disconnect from the throttle body (just have to loosen a screw to a clamp to do this) and to spray the MAF cleaner in this. He said to let this dry for about 30 minutes. Since I have half a tank of 87 gas in my vehicle, he said to add some octane boost to the tank. I called another Autozone for another opinion. He said that I do have a MAF sensor and the other person must have missed it. He said to take it off and clean it and follow the other advice (about the grade of gasoline)

Can anyone give me any insight into this? Any opinions as to what I need to do would be greatly appreciated.

On another note, I know I also need a tune-up. I have put about 80,000 miles on the vehicle (total miles on truck is 103K) and have never had a tune-up. I am not noticing any misfire, however. It does not run "rough". My brother said that he thought that plugs and wires are not probably causing the problem, although he said I still need them replaced. He said that he did not think that needing a tune-up would cause a check engine light to come on unless it was misfiring very badly. I do plan on replacing the plugs and wires but I have to wait until my brother comes to visit this Easter (I am trying to avoid paying Firestone $300 for plugs and wires, when I can buy them at AutoZone for about $60 if done myself).

I had a friend with same problem listen for vacuum leaks we found his under intake plenium area you have 2 elbows rubber that usually get frail and leak 1 by back wall passenger side other by top center front of motor connected to the same plastic tube this leak caused 12 codes.

I have a Ford F-150 4.6 V8. The RPMs has started to surge up and down while driving at a constant speed. If I take it out of overdrive it doesn't surge. It starts fine and no missing. Changed the fuel filter today. No change. I have a K&N air filter. I also cleaned it with their kit. No change.

I took the truck to the ford dealer. They hooked it up and no codes came up. They couldn't find the problem.
I changed out the fuel pump module above the spare tire. This did not help. I drove it a couple miles and the engine died when I pulled into a parking lot. It started right up and I drove it home. It died when I pulled into the driveway. It will restart, but while idling, the rpms will raise and drop by 100-200 rpms. It used to ony surge when I was driving in overdrive at a constant spead.

I haven't tryed cleaning the throttle plate yet, but plan on it over the holidays.

I have a 2002 F-150, I bought from a guy it's a great truck but having minor issues, this time I am wondering why when I am setting in park the truck is idleing fine but when I turn the heat on my rpm gadge goes up and down turn a/c or heat o of it stops, what would cause that?

So I replaced the IAC valve & egr which we dertermind were definatley bad. But after driving the truck for 40 miles it is still idleing rough. It did just set a code but don't know what it is yet. Could it be the MAF? (Reguardjng the 2000 F150, 5.4)

My idle fluctuates/surges from 750rpm(approx) to 1250 rpm(approx) normal operating temp, I have cleaned the Maf sensor and throttle body - and seems to be particularly hard on fuel (and yes I realize it is a truck lol) other than this the truck runs wonderfully with no hiccups

I had this problem it was a bad PCV hose in the rear of the engine FYI

Have a 2000 F150 idles rough, ocassionally dies at idle. Replaced egr valve & censor, vacuum looks good. What to check next. Says it's too lean.