Start off by saying this site ROCKS ....Little help....I towed my boat last week and noticed my truck sputtering around 1500rpm on the way home. Took the boat off still sputtering around 1500rpm under acceleration. Finally a code popped and it was P1405. Found the problem on here and fixed the hose (it had a tear in it). Today im driving and its still sputtering at 1500 rpm under acceleration here and there. Im going on a long trip this weekend and dont want to be on the side of the road. Any body got any ideas what it could be? I have not changed the plugs or coils.


I have 2001 F150 supercrew 5.4 V8 133k 4x4.

 

In normal operation the EGR system should be undetected by the owner. If the system fails with the EGR valve closed there will be no driveability concern. No MIL light means that the owner will remain unaware of it. Since emission testing is at idle (when the EGR does not operate) the vehicle will not fail the MOT (monitor). I know, you had a CEL.

However, if the system is not gas-tight then air can be drawn into the inlet system instead of inert gas. This can weakens the mixture sufficiently to cause misfiring, and manifests itself as a noticeable misfire/hesitation at speed and light throttle, not present when accelerating. If the leak is serious enough it may manifest itself as a hunting/rolling idle, caused by an unmetered leak of air into the inlet.

1405 is your EMS (Exhaust side) before orifice. The hose furthest down on the pipe, just so you know.

You have one of three possible problems, or all. Either your valve isn't closing completely, you have a low grade misfire because of a weak coil and/or a blockage.

 

Can you accelerate normally to 45 mph. At 45 mph , just after the shift into OD, - is this when you notice it missing the most ?

 

If you have 133k on the original plugs, you are definitely overdue.

 

Yes it does happen at between 45 and 55. Anything around 1500rpm it happens. I just noticed the truck at idle is now lower than usual roughly 6 or 7 thousand rpm. (Could be normal just cause im noticing everything now)


GLC honestly I have no idea if they are the orignal plugs or not. I just bought this truck at 126k and not sure what has been done to it.

Ill replace the plugs and coils if I need to no problem. Does anybody have a problem with them stripping out? I heard about them popping out or stripping out?

 

They only strip out if you undertorque them - they will loosen and blow out. 28 ft/lb dry with no antiseize works good, use Motorcrafts.

If you need coils, you can get a whole set for about 80 bucks on Ebay from Global or Uneek. Look for DG508.

 

Sounds like a low grade misfire. I ended up changing all my coils out @ 185,000 miles and it made a world of difference at those miles. Yea, when the miss is more pronounced @ 45+ after the shift into OD, it's a weak coil 99% (if not 100%)of the time. Their all getting tired most likely.
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You idle should be between 700 - 750 Rpm's. Any more or less is a problem, but that's not usually ignition related.

 

Guys thanks so much. I'm gonna try to change the coils and plugs and get back with results. I def noticed it at low acceleration so I hope it's the coils.

 

Is there a way I can find out which coil it is? I'm going to the lake and need my truck this weekend. Something to hold me over.

 

You can try to get it to throw a CEL - drive it to where it starts missing, and try to keep it at that point. When it runs rough long enough, it may finally trip it.

 

So I was driving to my brother inlaws yesterday and my spark plug blew out of the motor....SUCKS....had new plugs in the truck and coils in the mail. Hope this aint gonna take and arm and a leg to fix. check out the pics

 

www.blownoutsparkplug.com

If you want to try to do it yourself with a Timesert, contact member "Galaxy", he has a kit for rent.

You just installed new plugs, or they were waiting to be installed? If you just installed them, you must not have heeded my suggestion on proper installation........

 

No they were sitting in my truck waiting to be installed. Im waiting for the coils to come in the mail so I can do it all at once.

What are the chances that the threads or not stripped out? Looking at the threads on the plug they seem fine. I havent looked down the hole yet just pulled the plug and coil out.

 

So just brought the truck home so far so good. Replaced all the plugs and coils had them put a timesert in on the 7th plug. Noticed it still idles a little low right around 5 to 6k. Any ideas what this could be?

 

I hope they used a genuine "Timesert" and not a Helicoil or other brand. The only commercially available repair that really works and lasts (other than the custom inserts from blownoutsparkplug.com) is a Timesert.

If it's idling low, you may have a dirty IAC. It wouldn't hurt to pull the IAC and the throttle body and clean them. The EGR passages in the throttle body love to clog up.