5.4l 3v Not Your Typical Stalling Issue
 

I posted something similar in v8 section so I hope I get some feedback on this one. Yes I've done my research and it's not the VCTs or Phasors, not the MAF or Vacuum leak.. I don't think.

So here it goes, my truck (2004 3v 5.4l fx4) does the typical burble and stalls at low RPM. It has new phasers, VCT Solenoids, new throttle body, TPS and module, new Fuel Delivery module, plugs, coils and oil right before I got it.

So it warms up fine, but will stall when it gets warm.

*** If I unplug either or both Camshaft Position sensors, it runs fine. If both are plugged in, it burbles and dies. I changed the Cam Position sensors and checked to see if there was a ground, no dice and still stalls.

No Codes thrown, no CEL

I've searched the threads and cannot find anything similar.

If you guys have any any ideas or have had similar problems, any help would be great!

thanks!!

DoubleDu4, welcome to the forum. I deleted the other two threads you started on this problem because we've found that duplicate threads or posts on a common topic lead to confusing responses that can waste your time or cost you extra money in unneeded repairs.

You say you have a new throttle body. Does that mean the MAF sensor is new too? Your symptom has some of the characteristics of a dirty or malfunctioning MAF sensor when your engine reaches closed-loop conditions.

I'm not an engine guru though. I'm sure someone will be along with better ideas.

- Jack

Thank you, I realized I accidentally posted it twice and couldn't figure out how to delete the other post.

I cleaned the MAF with MAF cleaner and it still runs poorly with both Camshaft Position sensors plugged in. I will look into swapping out my MAF for a new one, hopefully it fixes it!

Thanks!

No codes, no CEL, the MAF is probably okay.

Finally threw a code today, P0345 bank 2 Cam Position Sensor circuit. Will be checking wires and connections, as well as the timing and solonoids.

Clean the throttle body too

Sir, I respect your opinion so much that I hesitate to disagree, but, I don't think that's quite right. I'm sure that a serious MAF problem would throw a code, but I know they CAN cause poor idle symptoms without generating a code. And, if he cleaned it, he could have damaged it (which I understand is easy to do). So, I'm suspicious.

But of course, this does not explain the P0345 code. And I have no thoughts regarding it. However, I find it interesting that the truck idled OK with the Cam Position Sensors unplugged. I wonder if that takes the engine out of "closed loop"?

- Jack

I very well could have accidentally damaged the MAF, always a possibility. I simply used MAF cleaner sprayed it and waited a while for it to dry, followed a few DIY but it's not really rocket science. Didn't touch any of the wires inside

And the throttle body and TPS are brand spanking new.

from what I've read, removing a cam sensor takes it out of closed loop, but hey, i could be wrong. Another member on here had a similar issue stalling, rough idle and P0345. and after spending lots to fix different things, found out his cam gear was off a tooth. Maybe the shop installed it one tooth off. I will be working on it more this weekend

I will also be getting it diagnosed and scanned by a Ford trained technician. Just emailed him today, waiting for a reply.

thanks again for your input!

OK, I suspect your MAF sensor is fine and glc was right as usual.

In closed loop, the PCM tries to control the engine based on what it has learned. In open loop, the PCM can adapt to different inputs better. So, now I'm making a WAG that in open loop the PCM can compensate for a cam timing that is not quite right.

And, that suggests you are on the right track, focusing on the cam gear.

- Jack