Slight Misfire when idling no codes

[Nomad8326]

Replaced:
-NGK spark plugs
-Bosch Plug wires

Cleaned
-Maf
-Dielectric grease at coil pack to wire connections

Only known issue gas tank evap appears to be messed up since I can only put a little over 1/2 tank of gas into the tank before it tries to spit it out the filler tube.

Seems to run smoothly when driving and was running better after i cleaned the maf but it was also 10F outside and when it warmed back up the misfire returned.

After sitting at idle it for a few seconds it seems to miss after randomly with no consistent interval sometimes 3+ seconds and other times one on top of another.

Any ideas?

 

[Number4]

You didn't post an engine size, but by XLS, I'll presume it's the 4.0?

I have the same issue, only noticeable at idle. Using the scan tool, yields zero codes and lists no misfires. I've been told that Ford doesn't register misfires easily.
Originally, I replaced the spark plugs and wires. definitely helped. Went from 13 mpgs to 17 over night. Plugs were old and out of spec.
However, still have this "slight" misfire feel at idle. I haven't been able to figure it out either.

 

[Nomad8326]

Silly me I'm used to vehicles only having 1 engine.

Yes 4.0L Flex

 

[chopperb]

Can you read the fuel trim with a scanner?

 

[Nomad8326]

Can you read the fuel trim with a scanner?

I think i might be able to program my scanguage to read it.

 

[miker104]

I have same issue, and have done the same actions (plugs, wires etc). Believe it to be related to fuel trims possibly a slight intake leak. Mechanic told me to keep driving it until the Check Engine light comes on.

 

[turborich]

The 4.0 liters are known to be rough at idle. Mine is rougher then I think it should be at idle but it drives great, no codes, passes emissions like new, etc. I wouldn't hesitate to drive it cross country. I have changed the wires, plugs, cleaned MAF, etc. Ford has a new program that may help the idle however I'm not gonna let them touch my truck.

 

[Explorer7813]

I had the exact same issue. Here's something to try. With the explorer running, pop the hood, wait till the "rough idle" or "misfire" starts and unplug the mass air flow sensor, this will be the one on your air intake tube (be sure to watch hand placement with vehicle running). It will prob smooth idling out. I did this and seen it changed the way it idled. So went and bought a new mass air flow sensor and replaced it and...problem solved!! Hope this helps

 

[Nomad8326]

I had the exact same issue. Here's something to try. With the explorer running, pop the hood, wait till the "rough idle" or "misfire" starts and unplug the mass air flow sensor, this will be the one on your air intake tube (be sure to watch hand placement with vehicle running). It will prob smooth idling out. I did this and seen it changed the way it idled. So went and bought a new mass air flow sensor and replaced it and...problem solved!! Hope this helps

Tried that and it stalled out instantly.

 

[Number4]

Be careful unplugging anything electrical while running or even off but with power applied. It's a good way to fry electronics.

 

[Explorer7813]

Another thing to ppssibly look at...in your original post you stated u had changed plugs and wires and all that...did u change the coil pack itself as well?

 

[Nomad8326]

Another thing to ppssibly look at...in your original post you stated u had changed plugs and wires and all that...did u change the coil pack itself as well?

No but it seems good.

I hate just throwing parts at things because usually you end up spending $$$ and have nothing to show for it other then you installed a bunch of new parts.

If we had some way to test this out and prove it was bad I'm all for it.

Anyways guy from work has one of those snapon Verus or however its spelled and we are gonna try and see it we can find something showing up but not tripping the cel.

 

[Explorer7813]

No but it seems good.

I hate just throwing parts at things because usually you end up spending $$$ and have nothing to show for it other then you installed a bunch of new parts.

If we had some way to test this out and prove it was bad I'm all for it.

Anyways guy from work has one of those snapon Verus or however its spelled and we are gonna try and see it we can find something showing up but not tripping the cel.

Understand that. I'm not familiar with a way to actually *test* the coil pack. On the f150s I used to have u could unplug going to each plug one at a time to test but not sure if that concept works on these explorers. Wish I could help more