Just began happening cold. I pulled up the maf sensor and it stayed running. Put in and shut off. Replaced maf and same thing. Use to do this sometimes only when hot and left off for about 15 minutes. Stays running once warm but hesitates.
This was a new one from blue streak I just put in, and i put the old one back and started fine. Where can i get an oem maf? I think it is going bad as it shows .11 to .19 flow even with engine off. When hot, it would buck at idle while at red light.
F50F-12B579-AA AFH80-01A 6H23

F50F-12B579-AA AFH80-01A 6H23

 

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What you should do is to CLEAN the connector and the wire using electrical contact cleaner or 91% isopropyl alcohol.
Additionally, does it stall at traffic light while driving? Can you restart it right up? Yes unplug the MAF electrical connector and drive, default air/fuel trim ratio should be kicked in, you should get very rough idling, but it shouldn't stall anymore when MAF is unplugged. Then that's a sign of a bad MAF. If it stalls again after replacing a new one, then it is not MAF issue but something else.

 

Instead of going on a wild goose chase, suppose we try this ?

A simple test light probe at the ign coil. With the key on one of the wires coming the coil should have power. Watch that test light after you start the vehicle cold/hot whenever the stall occurs.. What we want to know is:does the light go out when the stall takes place. Yes/ No .

If the light goes out, we have one problem. If it stalls and the light doesn't go out , we need to know that. Can you do this and get back to us with an answer, thanks.

We can come up with a logical diagnostic path and hopefully isolate the problem area.

 

Turns out the maf from oreilly was defective. Found a new oem finally and replaced. Replaced pcm, fuel pressure regulator. After 100 miles got po300. Finally checked the new fuel pumps pressure again and now it's showing 23lbs. Should be 45 so it seems to be defective as well. Should know by next week.

 

Replaced the fuel pump and still showing 23lbs. Still same symptoms. I'm at a loss, new oem pressure regulator too

 

 

Very helpful, thank you. Will keep you posted.

 

Another mechanic diagnosed all day and thinks it is the Ignition Pickup Coil. I had the coil done thinking it was done already but he says it's different. Now where do I find a motorcraft one and do you agree this could be it?
I found one made by Wells. Then the mechanic asked for me to get it all and one assembled unit which i don't understand what to look for.
Supposedly the fuel filter caused the low pressure and he claims it is now showing 35. I dont know if he is jerking me around and his guage was off becasue i dont see how a clogged filter could make the pressure stop at 23. What are your thoughts?

 

Sometimes, after hot, in gear, give it gas with load, it will hesitate or feel like a misfire sometimes then provide full power. At times, it may even die.

 

Finally replaced the dpfe sensor. Issue is now almost all the way gone yet i still get a pending po402. The egr seems to be working well yet don't know why it seems to open too often or much at low rpm. Still troubleshooting.