Engine running ruff after a full day of travel any ideas

So my 2011 Ford E-450 V-10 only has less than 30k on it . Runs like a champ until the end of the day after about 300 miles on the open road. Then Im noticing and feeling a Ruff chug chug chug at very low rpm. When we slow to a stop sign there is is ruff- idle, until I put some fuel to it and increase the rpm. This is something new that just started. A new Air filter was put in less than 10K ago and the old one was really dirty. I will take a look at the new one and put in a new one I have on hand and see if that helps. any other Ideas?
Im thinking its a fuel air issue

thanks
 t

With no check engine light (CEL) , might be a little tough to find.

1) Try going to an auto parts chain store that reads codes and see if there are any pending codes in the P03XX  series, engine misfire detected. the 'xx' will be 00 for a random misfire, or 01 - 10 if it is a specific cylinder. (ie: code P0304 means a misfire on cylinder 4)  This can pinpoint an ignition issue, or help find a vacuum leak. (this P03XX series is OBD2 mandated, so any code reader can see it. Not like the factory diagnostic codes..  )

2) the Mass Airflow Sensor (MAF) is after the air filter, and sometimes when a dirty one is removed particles get past and clog it. There is a simple spray that cleans it,(  https://www.walmart.com/ip/CRC-Industries-05110-Mass-Air-Flow-Sensor-Cleaner-Wt-11-oz/39950006?wmlspartner=wlpa&selectedSellerId=1122&adid=22222222227028232711&wl0=&wl1=g&wl2=c&wl3=60525702969&wl4=pla-95221774089&wl5=9011833&wl6=&wl7=&wl8=&wl9=pla&wl10=101593696&wl11=online&wl12=39950006&wl13=&veh=sem&gclid=EAIaIQobChMIiN2RhIbk4gIVj56fCh2hEA6wEAQYASABEgKNTfD_BwE ) and that has solved rough idle issues before. Can help fuel mileage too. Might be a pending code in the P017X series if this is the case.

""CLEANING FORD MAF SENSORS
For some reason, Ford vehicles have had a history of MAF sensor problems caused by contamination. In some cases, dirt gets past a leaky air filter and fouls the sensor wire. In other cases, carbon varnish builds up on the sensor from fuel vapors backing up through the intake manifold. Either way, contamination makes the MAF sensor sluggish, and often sets a P0171 or P0174 lean code.

The fix is to clean the sensor element with aerosol electronics cleaner (CRC makes a good product for this). The MAF sensor is located inside the air filter housing on some applications (Windstar, for example) or between the air filter and throttle body. Spray the sensor element with electronics cleaner, let it soak for about 10 minutes, then repeat. DO NOT use any other type of cleaner as this may damage the sensor. Also, DO NOT touch, scrub or attempt to physically clean the sensor element as this too can ruin the sensor.""

source - https://www.aa1car.com/library/maf_sensors.htm

(When I clean them, I will give them 4-5 soak-wait-rinse  cycles with the spray. Do something else while you wait, or you will rush the process. May take 45 min to an hour total. I do this task thoroughly ONCE, as I do NOT like come-backs from customers. )

3) a slow acting IAC (Idle Air Controller) can also cause rough idle, but really requires a scan tool to properly diagnose. Or you can be a shadetree mechanic and just throw parts at it until something works. 


My top 3 guesses.    In order. If no CEL or pending codes, I would look at cleaning the MAF, especially after the problem seemed to arrive after a dirty air filter change. 


Good Luck!

Volkemon,

I got a P0191 code on my trip up to Canada. It’s a fuel pressure related code. Engine ran fine and fuel mileage was great.  I cleared the code with my Scanguage.  It seemed the code happened after restarting the engine. When I cleared the code the check engine light stayed off until I restarted the engine and after refueling. I replaced the fuel pump module last fall when I couldn’t get the engine started at all and that solved that problem. Any ideas what’s causing it?  Could it be as simple as needing a new gas cap?

I bought some sea foam has anyone tried that  for cleaning the injection system would that be something to try?

I've been using SeaFoam for a lot of years , occasionally in my cars but all the time in my power equipment, haven't had carb or injector problems since using it . I'll put 1 oz per gallon in our Trend if it will be sitting for awhile and run generator before sitting so it gets a dose too . If you're having some running issues I would run at least a couple tanks full , adjust dosage of oz/gal when topping off or refilling don't want to put too much in there . Good stuff !   

Volkemon,

I got a P0191 code on my trip up to Canada. It’s a fuel pressure related code. Engine ran fine and fuel mileage was great.  I cleared the code with my Scanguage.  It seemed the code happened after restarting the engine. When I cleared the code the check engine light stayed off until I restarted the engine and after refueling. I replaced the fuel pump module last fall when I couldn’t get the engine started at all and that solved that problem. Any ideas what’s causing it?  Could it be as simple as needing a new gas cap?

Not quite clear... is the timeline:

CEL with P0191 code, no driveability problems. Cleared code, code returned after restart. Engine had no-start condition, replaced fuel pump and solved no-start problem..... and the CEL?  I am gonna assume you still have the P0191 code lighting the CEL regularly.

Loose cap would give a P0465/P0467 or other EVAP leak code. This code (P0191) indicates there is "something wrong"  with the readings the fuel pressure sensor is reporting back to the ECM. By "something wrong" I mean the numbers that the ECM is 'seeing' are not within the limits that are expected.

It doesnt state WHAT the problem is, but indicates that other tests are needed. If a P0191 code keeps setting, one would check fuel pressure readings, especially when starting. Then in conjunction with the pressure gauge, observe the readings the sensor is sending to the ECM, preferably with both an active voltage reading on the sensor output and observing the value the ECM is displaying. If your scanguage displays the fuel pressure from the ECM then you can use a pressure gauge on the fuel rail to see if the readings agree. This could tell you if it is a sensor or low pressure on start triggering the CEL.

I bought some sea foam has anyone tried that  for cleaning the injection system would that be something to try?

They do sell a lot of it, and I have had many people say they run it 'all the time' and have no fuel problems. I do not use it at all, and have no fuel problems.  Must work like elephant repelling powder..

""A man is sprinkling a powder all over the streets, when a policeman walks up to him and asks what on earth he is doing. The man replies saying keeping the elephants away of course! It's elephant repellent!
The officer replies, don't be absurd, there are no elephants here. The man replies saying then it must be working!"" 

I have used it several times in the past, and have yet to ever have the intake manifold cleaning procedure do anything noteworthy but to blanket the area in a fog.  That does make an impressive sight, however, and might be worth doing for the experience alone. 

Volkemon,

Thanks for the reply. Yeah I guess my timeline was a little cloudy!  Last fall the engine would not start. No CEL. When I turned the key to the ON position I could hear the fuel pump turn on. That’s why I replaced the fuel pump module and that solved the no start problem. The CEL P0191 code happened a couple weeks ago on our trip up to Canada. It first came on shortly after refueling. I cleared the code with the Scanguage and got no further codes until another restart after stopping for a lunch break. The engine seems to run fine, no hesitation, easy starting, plenty of power, and good fuel economy. I will check it further as you suggest. Thanks.