mmnewcomb

I've searched all over and haven't seen a thread with the same issue I'm having, so that's why I am starting a new thread, so please don't yell at me

I have a 07 F150 3V 5.4L with about 56k miles.

Since I've had the truck (bought in June 2014 w/ 49k miles) in warm weather I have a rough idle/stall issue. Didn't happen all winter, only in the warm weather. It's gotten very bad to the point where I'm nearly stalling/stalling multiple times a day. Usually happens in situations where I'm barely gassing it (fast food drive-thru, backing into a parking space, coming to a stop light).

In addition to this, when my truck gets up to normal operating temperature, I have zero acceleration. I'm attaching a video to show how slow it accelerates from a stop.

I have an Injen intake on the truck. When I installed the intake I took the throttle body off and cleaned it because I had read that that solved a lot of people's rough idle and stalling issue. I also cleaned the MAF while it was off. Neither of these solved my problem.

I'm at a loss here. At first I thought it could be a fuel-delivery problem, so I am changing the fuel filter ASAP. But the thing that confuses me is that the acceleration problem does not happen until normal operating temp. If I start the truck in the morning and drive off after a minute it has amazing acceleration. But as soon as my temp gauge gets to its normal position it turns into what you see/hear in the video.

Here's the link to the video:
Help please!

graywolf

See if Advance Auto or AutoZone will put their portable OBD II engine analyzer on it and determine the issue. They usually do not charge a fee. But they need your engine computer to give a code to the OBD II. The "warm weather only" is real strange. As always, there may be a bad sensor of some sort.
I had an issue with stuttering when my engine was cold, going slightly uphill and only at 40 mph/1000 rpms......a spark plug change cured the problem. Best wishes.

mmnewcomb

The CEL has yet to come on since I bought the truck. I know sometimes the computer will have codes stored without a CEL but I haven't gotten it checked yet.

mmnewcomb

Just to update here, after reading many different articles and threads I'm going to start hunting for a vacuum leak today. With it seeming to run lean and no CEL I'm thinking it's possible there is a small leak. Will update my findings later.

graywolf

Good luck. It sounds like a mystery. My 08 F150 with the 5.4 3V never showed a code before my plug change cured the problem.

powerranger262

If you think it's running lean, then that intake isn't helping without a tuner.

mmnewcomb

Yes I am going to be getting an Edge Evo HT in the near future.

But if there is a vacuum leak or something causing a lean problem in the truck I'd rather find the problem and fix it than just put a bandaid on it.

Ranger621

I would check your EGR valve. I had a similar issue with my 99 F150 5.4 ltre and it was the EGR valve.

Tommy J

Thank you. It seems "put a tuner on it" seems to be the cure all. I agree with the band aid comment and finding the real cause. Please update if you fix it. I've replaced plugs,cops and a host of other things and probably have a different issue than you with a rough/low idle and hesitation but have yet to solve my issue. I do agree though with the easy fuel filter first and of course any codes. FYI, I picked up a good inspection camera at Lowes for like $65.00 and I love it. Great for getting back behind manifold for checking vac hoses. Good luck

Especial86

iTrader: (1)

That video shows a pretty big lag in the speedometer vs the tach.. Maybe you torque converter is slipping too much.. A fluid change certainly won't hurt, or at least a quick check on the color and smell of the fluid..

Before suspecting tranny too much, the tps sensor, and all electrical connections are worth a look. The motor seems to rev clean, if it's rough idling is it doing it in park? Or in gear? Or both?..
Try using the AC and headlights to see if loading the motor smooths out the idle by jumping the RPM's higher.

A tuner does help this "lag" and "low rough idle" problem, because the ford factory tune is designed to appease grandpa, mom, dad but not the son... These trucks are all borderline dogs without at tune..