I have an 04 F150 5.4 FX4 with 150k on it. I had the whole timing system done (chains, phasers, solenoids, etc) done about 3k miles ago, been running like a beast ever since. The last week or so its been sputtering (sounds like a model T) for about 5 seconds when I come off the gas. its worse when im turning, and lasts until i back off the gas. Sometimes when turning at low speeds, it sputters almost to a stall. Its been getting progressively worse since it started, lasting longer and sputtering worse. Power steering fluid was found to be really low (dont know how the shop missed that) but topped it off with no result.

Today, just for fun while i was watching it run (trying to spot something obvious) I popped the latches on the air cleaner and pulled it out about 2" and the truck immediately sputtered to a stall. Replaced and restarted, pulled the air cleaner tray out a couple inches, and it stalled again. Sometimes it runs for a few seconds under duress then stalls, sometimes i stalls right away. I know too much air will cause it to run lean, but that should take a few minutes and not lead to a complete stall, correct?

Is this an issue where I need to replace the filter and disconnect the battery for a few mins, or is there something more sinister that would cause it? The air cleaner is FILTHY, but im afraid replacing it will cause it to stall in traffic, where as it at least runs now. fuel filter? bad/dirty MAF? im at a loss here guys.

thanks in advance.

 

I'm going to be honest you have me stumped at the moment.. is the cel on

 

Replace the air filter - you said yourself that it is filthy - good chance some contaminants have gotten through. Clean your MAF, run some seafoam through, and check the foam gasket on your filter tray - if you haven't replaced it before, I can guarantee you that it is rotted either partially or completely away .

 

Fixed! The shop did an oil change when they did the timing system. I knew the engine was a little low on oil. Was maybe 1 or 1.5 quarts down after sitting a while. I grabbed 2 quarts to top it off and today after not resting, the oil was way down. After 2 quarts it wasn't even on the dip stick. 4.5 quarts later he noise is gone. I suspect the shop used an el cheapo oil filter that's letting the oil flow back out of the engine when it's off. Hope this helps someone else.