Rough idle / lean after warming up

[Vr1967]

Have a 2007 Explorer EB 4.0 V6

Did a search, but didnt turn up anything similar

Recently it has gotten where when it get to 165-170 degrees (per a Scan Gauge 2) it starts running very rough, then dies.
Before, wife said it would occasionally have a “dead pedal” so the throttle body and pedal were replaced. She ran it a while and now this.

Today was the first day I have had time to mess with it, due to work, (and having a 3rd vehicle)

Vehicle has had plugs, wires, tb, pedal, coolant temp, crank position, and fuel rail pressure sensors (at which time upper intake and valve cover gaskets were replaced) in last 10k miles

Only codes it is showing at moment are P2195 & 2197

MAP sensor was reading steady 4.4 until it warmed up then it went erratic with the idle.

Runs perfect until it gets up to operating temp.

At what temp does egr start to open? What else is temp controlled that I need to check?

Been wrenching on my own stuff for 40 plus years, but the newer electronic stuff stumps me now.

Thank you for any input

 

[Rcflyer330]

With both sensors reading lean its unlikely the o2 sensors are bad or its a pcm issue. It still could be but unlikely. things it could be; wiring, a vacuum leak, fuel pressure, egr valve, pcv valve, or anything fuel or air related. on your scan tool watch the live data for fuel pressure, b1s1 & b2s1 o2 sensors and confirm they are reading lean and fuel pressure is not low (should be ~30psi or more). If you have freeze frame data look when the codes where set to see if anything looks off.
The egr valve should always be closed at idle if it is leaking it would be just like a vacuum leak possibly causing the symptoms.
while I am no professional I would lean more towards wiring issue or vacuum leak because you have codes for both sensors.

I am guessing this issue started after you had all the work done? If so look over all the hoses that connect to anything that may needed to be removed for the work that was done. its possible that a hose was not connected or not connected all the way and fell off. also may be a good idea to check for vacuum leaks in around the intake manifold just to be sure.

 

[Vr1967]

Plan to get back on it Tuesday. Thank you for the suggestions

Have a program to do Monday on those perished from our county defending our country.

Lest We Forget

 

[Vr1967]

With both sensors reading lean its unlikely the o2 sensors are bad or its a pcm issue. It still could be but unlikely. things it could be; wiring, a vacuum leak, fuel pressure, egr valve, pcv valve, or anything fuel or air related. on your scan tool watch the live data for fuel pressure, b1s1 & b2s1 o2 sensors and confirm they are reading lean and fuel pressure is not low (should be ~30psi or more). If you have freeze frame data look when the codes where set to see if anything looks off.
The egr valve should always be closed at idle if it is leaking it would be just like a vacuum leak possibly causing the symptoms.
while I am no professional I would lean more towards wiring issue or vacuum leak because you have codes for both sensors.

I am guessing this issue started after you had all the work done? If so look over all the hoses that connect to anything that may needed to be removed for the work that was done. its possible that a hose was not connected or not connected all the way and fell off. also may be a good idea to check for vacuum leaks in around the intake manifold just to be sure.

Scanner I borrowed wasn't the best as you have to scroll thru numerous screens, but showed fuel pressure greater than 38psi. B1S1 & B2S1 both were consistent idling before it started stumbling, and I could not get back to the screen before it died. No freeze frame. If so, not sure how to do it.

Did change out vacuum lines to FRP/egr/ac. It blows out dash vents good again!

I sprayed some starter fluid around intake and egr valve when it started stumbling with no change.

Cleaned MAF sensor, but need to figure out a way to test it, and study up on the egr.

It idles, runs, drives perfect until it gets up to temp.

Had something come up so will get back to it tomorrow.

 

[Vr1967]

Got to mess with it a bit more today. Found and covered bare wire spots near most of the connectors. It is idling much smoother.

It is stumbling / rough idle earlier now than before. Not getting much response from MAP readings if you ease into the throttle, only if you rev it and let off quickly.

Can’t find a vacuum leak so going to swap MAP sensor/EGR valve assembly, as much as I hate just swapping parts.

Will cont to update as I get to work on it.

Appreciate any input or suggestions from anyone,

 

[Vr1967]

Did get egr swapped, with no change.

It starts running rough sooner now, but outside temp is getting hotter than when I was messing with it before.

Now have a SnapOn Modis scanner/diagnostic tool, but have had very little time to really mess with it. Did run it thru the evap/vacuum leak checks with no issues found. Still figuring out the Modis, as guy I borrowed it from asked me to show him how to run it! I did do a crank relearn and a few other checks on a Suburban with it.

Hope to get back to it this weekend.

 

[JAWIT]

I had an issue where my 2008 4.0L would idle poorly if I restarted it once the vehicle was up to operating temperature. It was intermittent, but would only occur once it was warmed up good. Cold start ups were fine. Mine eventually threw a code related to a fuel issue. Don't remember which one. It ended up being the EVAP purge valve under the hood. Looks like the below. If you do end up replacing it, I'd recommend only getting the Motorcraft part. I also replaced the length of hose that attaches to it from the intake. Just take the old hose with you to the parts store and can cut to length.

 

[Vr1967]

Changed MAF, pcv valve, evap purge valve, a couple vacuum lines and such. Idles smooth as heck (it has never idled that smooth) BUT it still all of a sudden goes to idling poorly and dies.

Plan to send ecm to SIA or some such to have it checked. With all the bare wires I’ve found, wonder if something shorted in the ecm.

 

[Vr1967]

ECM and coil pack has been changed with no luck.
It will not get up to temp now, only running about a minute, but it starts idling rough now. Up until then, it idles as smooth as a new vehicle

 

[Rcflyer330]

is it still giving codes? if you still have the o2 sensors stuck lean codes then check connectors and wiring for the front o2 sensors. if you dont find anything try unplugging the MAF sensor and run the engine this should put the vehicle into a default fuel ratio mode see if it runs better for a longer time and this will throw a check engine code. if it runs longer then you know the engine is either getting too much air or too little fuel.

 

[davidmmm69]

Have you ever watched pinehollowdiagnostics on you tube, really amazing at finding these issues. Anyway on occasion and also just recently he got the extreme parts cannon where the customer went crazy swapping parts with aftermarket junk,
Just remember ,
One of hardest things to explain to customers is that new and good have 2 different definitions!!!

 

[Vr1967]

Have had little time to mess with it due to wife’s health issues, and helping daughter/son in law with getting ready for the grand daughter that should be here in a month.

I did unplug the MAF with NO change in how long it runs. Will try to start checking wiring etc as I have time.
May- may have found an older Ford mech/tech I can take it to. Hope to see him this weekend and will go from there

Thank you for everyone’s input so far

 

[Vr1967]

Update:

Progress has been slow with wife’s health, but did make a little headway today. Today I swapped the fuel pump out and was able to drive it for the first time with only one issue. It died once, while driving, put it in neutral and recranked without another issue.

I’m guessing the fuel pump was overheating causing the issue.

Did forget to pick up a new fuel pump relay, but will grab one after church tomorrow along with some fuel treatment, and run it a good bit more. It’s got 1/4 tank of almost year old gas in it.

 

[Vr1967]

Got a P0451 code, but fuel tank is now pressuring up, so going thru evap system trying to sort that. (Purge valve under hood was changed earlier) did unplug vapor vent solenoid under rear of vehicle, but that didn’t release the pressure so going to start looking from the tank forward.