F150 Idle problem
Hello all. I am obviously new here, but I figured I would turn to a forum to maybe help me with my problem.
About a week ago I put $20 of fuel (about 6 gallons) in my truck. It was getting low but not out by any means. I drove about 200 yards and the Check Engine Light came on. When the truck idles it spits and sputters and wants to die. Also under decelleration it feels and sounds like the engine shuts off until i apply the throttle. Anything over idle it runs fine. I have 143K miles on this truck and have never had an ounce of trouble out of it. It is a 2003 F150 4.6L 2WD by the way.
I went to the gas station about an hour later and told them of the problem. They said more people would have to complain before they would do anything. I went back a few days later and no one else had complained. So I took the truck by autozone and they put their "check engine light tester" on it. It read code 171 I believe it was. It had four possible areas of the problem which where O2 sensor, mass air flow, fuel injectors, and one other thing that I cant remember but I dont think it was it whatever it was. I have a friend that has a more hi-tech tester, we used it, and it said the O2 and mass air flow sensors were fine.
Now what I have done so far to potentially remedy the problem to no avail. I changed the fuel filter, ran a can of Sea-Foam through a full tank, and cleaned out the IAC valve with carb-cleaner. I was told there was a good chance it could be the IAC valve. I noticed the valve was deployed about 1/2" inside the unit. Out of curiosity I took a small screwdriver and gently tried to close to valve. It would not close, but I didn't know if it was supposed to or not? Mind you I put little pressure on it in fear of damaging the valve. After putting it back on the truck still sputters, but it sounds like it runs just a tick better but nothing to get excited about.
Basically I am trying to avoid taking this to a mechanic, because I feel it is a small problem that I can fix. Also while standing and hovering over the engine, it sounds great. It purrs like it always has, just the missing that you can hear mainly by the exhaust tips. I have dual exhaust on the truck also. Any help is appreciated.