i have a code of P0405 and i also have what feels like a missfire but is very significant when it is cold and once the engine is warm i can not feel it as much. could the dpfe have something to do with the stuble and only happening when it is cold? I dont want to change something the does not need to be changed.

 

First things first - Are you absolutely sure it's 405 ? If so , this is the first case I've heard of .

Well that code IMO means hose failure from the DPFE. Check the hoses thoroughly, most likley your DPFE sensor itself is fried. Get one @ Ford only.

You could have a bad EGR valve to add to the problem. But your not getting a code for it. I wouldn't think twice about throwing those two parts at it if I had high miles..

You could also have a bad coil. It might be a good time to update this hardware and clean your TB and Elbow.

 

Yes i am positive that it is p0405 i looked at the machine and that is what it came up with. i checked out my dpfe and somehow the hose actually fell off reconnected it and have not yet reset the light but i still have the stumble when it is cold that is prominent i am going to disconnect the dpfe sensor and try to drive while cold to see if it does the same thing. I was thinking maybe coils also but that would do it all the time correct?

 

If the stumble is more prominent when cold it is the IAC that's giving you the problem most likley. The O2's come into play once the heaters put them @ 800 degree's ( once the engine warms) . The IAC still plays a part , but a much smaller one.

BTW - This is how you fix that if you don't want to replace -

________________________________________________

The IAC is located on the back of your plenum (throttle body elbow) - there's 3 IAC's in this pic -



Clean with a product called "DeepCreep" , made by SeaFoam .


Here's what you clean -




Procedure as follows -

Saturate w/DeepCreep. Work the mechanical's inside the IAC (plunger) to break free carbon deposits. Blow out w/compressed air. Repeat two or three times. DeepCreep cleans and lubes the IAC at the the same time and won't hurt it. Other products will.

 

thanks jbrew. i do not have to take the intake plenum off to get that off do I. also what do you mean by work the mecanicalsl? am i supposed to take like a qtip and work that around?

 

No, you can do it without taking everything apart, - It's not the easiest thing, but it can be done..

 

thanks jbrew i am going to give it a shot tommorow. whats the best way to clean in there or just let it soak then blow it out. or should i rub around in there with a qtip?