A miss all of a sudden!

[Vinniety]

***This is for a 2000 Sport OHV motor***

A few months ago roughly 7K miles ago I had a check engine light on and a random miss. I did a complete tuneup with all motorcraft parts. Plugs, wires, gas filter and a K&N drop in filter. The problem still was there so i did the upper and lower intake gaskets. Problem was now resolved.

This morning i get in the truck and it ran great. After work this is when i noticed the problem....I have another random miss...I checked the wires by pulling on them and checking for any arch markes and nothing. The air filter is also clean. I dont have a check engine light on yet so i cant run a scan. Can this be a bad plug or maybe the gaskets once again? I dont think it is the gaskets but again i dont have a real answer just yet.

My question is for you experts what can it be? From my experience a miss is a bad plug, wire or a vacuum leak. I dont hear a vacuum leak but i know the test i did where not 100% accurate. What do you guys think?

HELP!

 

[btexpress]

Even without the CEL on there may be a pending or memory code which might at least lead you to the offending cylinder. I have experienced many, many Fords with dead misfires that never set the CEL.

 

[andy123]

Mine does this too. I think my miss is caused by DPFE sensor starting to go. I am changing it tomorrow morning.

 

[Vinniety]

Mine does this too. I think my miss is caused by DPFE sensor starting to go. I am changing it tomorrow morning.

What is that? DPFE sensor?

 

[aldive]

What is that? DPFE sensor?

DPFE = Differential Pressure Feedback EGR Sensor

 

[Turdle]

Mine does this too. I think my miss is caused by DPFE sensor starting to go. I am changing it tomorrow morning.

I don't see how this can cause a miss. If it goes it will throw a p0401 or p 0402 code, but it has nothing to do with ignition. It is merely a monitor-

 

[Vinniety]

i plan on taking the plugs out this weekend and see how they look. I do know that when i pull a wire from the coil pack the arching is very blue and very strong. I guess a bad plug. THat is all i can think of right now.

 

[Gator Jeff]

i plan on taking the plugs out this weekend and see how they look. I do know that when i pull a wire from the coil pack the arching is very blue and very strong. I guess a bad plug. THat is all i can think of right now.

If you don't have some elbows and wobbles, that rear driver's side plug is going to be hell to get out. Even with those tools, it's a serious PITA. I attempted it once and nearly screwed up the block. The Ford mechanic (who fixed my mistake) that I talked to said that SnapOn even makes a tool specifically to remove that plug in the Ford 4.0 OHV. Have fun.

 

[ThePhoenix]

i had to take it somewhere after I cracked a plug on the passenger side...what a PITA

 

[Vinniety]

I have plenty of tools that make it easy for me. Im not worried about that at all. I have done it a few times. I had a mazda pickup that had the same motor and owned that for about three years.

Thanks though for the look out!!

 

[andy123]

I don't see how this can cause a miss. If it goes it will throw a p0401 or p 0402 code, but it has nothing to do with ignition. It is merely a monitor-

Here is what I read in a Ford article;

When the DPFE Sensor starts failing, it gives the PCM bad information. The DPFE Sensor is less sensitive, and the PCM thinks less recirculated gas is being burned than is actually so. Trying to compensate, the PCM opens up the actuator too much. This excessive amount of EGR combined with the air coming in via the throttle body leans out the fuel mixture, causing a lean misfire, which is the "stumble" or "hesitation" that is common as the DPFE Sensor fails. The DPFE sensor in the Focus is not very robust, requiring frequent (every 30k miles or sometimes less) replacement or a work around. Note that complete DPFE sensor failure is a very slow process, and the check engine light won't come on until the DPFE sensor is pretty much done for.

Also read the Explorers were common for this too.

 

[ThePhoenix]

great find...

 

[Vinniety]

Well just wanted everyone to know that i changed my plugs from the motorcraft platinums to the autolite AP103's Gapped at .54 and i have to say wow. THe truck runs great. I think autolites are a better plug for my truck. Thanks everyone for the help.