Hello all - I have a 5.4L engine, I've been having a rough idle lately. It feels like stalling when I'm in park, or at a stop. It seems fine when I'm in motion, driving. It's an intermitting problem, there are days it drives normally. I don't have a check engine light on. I changed air filter and fuel filter, but no help. What's next? Oxygen sensor? Spark plugs? Thanks for your help.
Just a couple of ideas... I'd clean or replace the idle air control valve (IAC).
After that & since it's intermittent, I'd suspect a coil, but you'd need a misfire code or something to figure out which one. I've read numerous topics on the various Ford forums concerning intermittent power loss & hesitation problems being solved by replacing a coil or coil pack. Similarly, idle problems are often times reported to have been related to the IAC which has a tendency to get clogged & gummed up w carbon n stuff.
I went to Autozone, and had the codes read.
P1131 - Ford - Definition; Lack of bank 1 O2 transitions
Explanation; ECM detected bank 1 O2 at its lean limit
P1151 - Ford - Definition; Lack of O2 switches-bank 2 sensor 1
Explanation; ECM could not adjust fuel trim because of a lean or rich condition.
P0174 - Domestic - Definition; Fuel trim bank two condition
Explanation; The ECM has detected a rich or lean Air/Fuel ration condition on engine bank two.
P0171 - Domestic - Definition; Fuel trim bank one condition
Explanation; The computer has recognized a rich or lean condition on one engine bank only
Ok people, first off thanks for the help. The problem became less intermittent, and now it think it's completely gone. I'm waiting for more time to pass to be sure, will keep checking for codes.
This is what I've done. I bought some spark plugs and changed out the four on the passenger side. The third and fouth ones had had a bit of oil on them. That worried me, but I read that that may happen if too much oil is added on an oil change. I had my oil changed at walmart last, it doesn't suprise me that they'd over fill while rushing.
I then bought a cleaner for the IAC valve, which is the same cleaner for the throttle body, and cleaned out the valve and the throttle body. After putting things back together, things have been feeling, sounding, running great.
I still need to change out the other four spark plugs on the driver side, and hope not to find oil on any of them. I am also going to do an oil change myself.
This may sound dumb, but why is it that even though my engine calls for 5w-20, because of it having alot of miles, people suggest an oil thats 5w-30/40/50?
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