Farmer John

This has probably been posted many times before, and if it has, feel free to move this post. In short, I have reviewed the sticky post about F150's running like a diesel, and I am looking for alternatives to a bad cam phaser(s).

I have a 2007 F150 XLT with the 5.4L V8 Flex Fuel engine, with just over 70,000 miles on it. It will occasionally idle rough, normally after it has been driven for 30-45 minutes. If it is extremely wet, when stopping the truck will simply cut out. When it is idling rough, if you put the truck in park, or give it a little gas, it will go back to running normally. The truck also would drop RPMs, fluctuating between 250 and 750 RPMs. The check engine light will occasionally come on, and after a while will go back out.

After the first time the check engine light came on, I took it to the local Ford dealership, at that time I was told that the camshaft had failed, and the engine was practically blown. I was also told that the truck could run for five minutes, or six months with this problem. I had it checked at another mechanics shop and was told that the error was in the cam shaft position sensor circuit. I had both cam shaft position sensors and pigtails changed.

If anyone has any ideas as to what the problem could be, outside of a very expensive cam phaser problem, please enlighten me as to my next course of action.

Mod (Ret.)

Carbon on the throttle plate, the MAF, or the IAC Valve are common items to check for rough idle and/or stalling issues.

Farmer John

A problem with the MAF sensor was something that occurred to me, and I was planning on changing that in the immediate future. I am not sure what you mean by IAC Valve. Looking through the repair manual I bought for the truck I have I see an IAT sensor, that has something to do with the MAF sensor.

Thank you for taking the time to go over this problem, for what must have been the millionth time.

ltarasoff

I am having the same problem with my 2007 F150. the truck runs great for the first hour and then in reverse and park seems like a rough idle. when i had the truck inspected two codes were popping up P0345, and P0349. when i bought the truck the guy at the dealership told me that these codes could be ignored and the truck would run fine without any problem. now talking to a shop he said the cam position phaser could be the problem and it would be a pretty pricey fix. Anyways just wondering if you had your truck fixed and what the problem and price was. I would really appreciate your help as i just bought the truck and would like to fix it right away.
Thanks

kevhead75

First off why did you buy the truck with a CEL? I would go back to dealership and ask them how they would like it if you ignore the payments.

Those codes indicate problem with the cam system. Could be cam sensors, VCT solenoids, or phasers themselves. I have read in mustang forums that faulty alternator has caused this problem but have no idea if that applies to the f150.

Farmer John

Itarasoff, sorry I did not respond sooner. I changed my cam position sensors, and both pigtails, which helped the problem, but did not solve it. As it cooled down outside, it seems to be doing it less, but with a specific outside temperature range of 40 degrees to sixty-five degrees. In any event, I was able to buy a new MAF sensor today, and it took about 10 minutes to change it. I will know by Thursday morning if that was the problem. Either way I will stop in, and let everyone know if it continues or stops for a while and starts back. But I would advise you of this, Haynes has a very helpful manual for repairs, get one. More so if you are planing on doing things as cheaply as possible, meaning doing your own repairs.

I am working my way from least expensive repair to most expensive. Basically changing all sensors, and any pigtails that appear damaged, before I start working on saving money for Cam Phasers, or a new engine. I refuse to believe that in less than 70k miles I have a blown engine, this according to a local Ford dealership. With what I bought the truck for, and the fact that I have properly maintained it, I would be very hostile if it is blown.


~Update~ MAF Sensor did not solve the problem. On my next day off I will break down everything and clean the throttle body.

Farmer John

As fall turned to winter, the problem got worse, now occurring at any outside temperature.

Last week, with some nerves about this affair, I added half a bottle of Seafoam to the oil. Drive the truck about 50-75 miles, changed the oil to a 5w20 synthetic blend. Before changing the oil, I added the rest of that bottle to the engine by using the brake booster vacuum hose. I let it sit while I changed the oil, about 30 minutes, started and idled the truck at between 2-4k RPMs. This helped the truck, I was able to drive it around 75 miles before it started the rough idle, 150 miles round trip. It only did so twice the entire trip.

Today I changed the Fuel Pump Driver Module. Truck had a round idle once in the 80 mile trip. In the process of installation, I unhooked both terminals from the battery, which reset the CEL, which has not come back on. Stopped in town, got a new fuel filter, replaced it, and found a cut in the fuel line, replaced the fuel line on the truck. I have not run the truck enough to say if this solved the problem, and I have contacted a shop to replace the exhaust system, since I found a nasty dent in the piping near the exhaust manifold.

More updates to follow as time allows.

Disposablehero

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Farmer John

Nothing I threw at the truck worked. While going to work last night, it started idling extremely rough, stalled out. When I got it restarted CEL was back on, and I have not had the time to have the code read.

Guess that leaves cats, plugs, and coil packs before we discuss new cam phasers or new engine.

Leveled F150

Have you tried sea foam! Mine had a Lil but of a rough idle and I used sea foam and it did wonders for mine!!