So it has been since 2011 I have been on this site ironically.

The truck..
2011 F-150 3.5l
150289 miles

The truck has developed a misfire/backfire under heavy acceleration and slight misfire when cruising and easing into the pedal to maintain speed at speeds of 55 and up. The truck almost acts like it is running out of fuel it will buck and pop as it speeds up. I can drive around town all day taking it easy with no problem. I am at a loss I have replaced many parts that the computer codes lead me to believe and it still does it. I am leaning towards the cats being clogged The issue did not arise until 500 miles after I changed my plugs. Funny thing is I had to deal with the issue for a couple hundred miles with no check engine light. I had my buddy scan it at the local ford dealer there were no codes but showed 3 misfires on cylinder 3 and 1 misfire on cylinder 2 and 5. I replaced all the coils after this. I have tried swapping the old plugs back in and the issue is still there. Today it showed codes P0151 and P0155. I believe the p0155 is when I disconnected the 02 sensor the other night.

In the last 1500 miles I have replaced

Motocraft plugs gapped at .30
6 new Motorcraft coils
Airfilter
Checked all wiring for chaffing
Disconnected both up stream 02s and truck runs the same.
My truck does have a hole drilled in CAC
Truck is straight piped.

I have also scanned the vehicle at idle and wrote down these values.

Baro Pres 98
Cat Temp 1 450 C
Cat Temp 2 445 C
02S12 V .720
02S22 V .719
02S11 MA Stayed near 0
02S21 MA Stayed near 0
Fuel Rail 1470
Rich/lean .987
Long Fuel Trim 1 -11.7
Long Fuel Trim 2 -6.3
Short Fuel 1 3.1
Short Fuel 2 .8

I am willing to all suggestions.

Thanks again



Nick

 

I would double check your plugs. There have been quite a few people that has cracked the plug when putting them in and they got the same problems as you. Also a few have got defective plugs with a fine crack on them.

 

Sounds like your CAC is full of crap... I've not drilled mine either, and have not done any of the other "fixes" either..

The 11's had this problem more than other's depending on where you live. More humidity areas seem to be the worst.

After 11, Ford started to do different things to the CAC to try to help with the condensation issue with the earlier models..

Not gonna say one thing works better than the other, as I have a 13 and it's CAC has a bunch of crap added to it to keep the condensation down, but might also affect performance?

Good luck!

Mitch

 

Mine has a slight buck/popping sound under the first couple of hard accelerations of the day. When this happens it also sets off the laser band on my radar detector. It will do it once or twice then stop and be fine until you turn the ignition off. Then the process starts over again. When this happens I notice a slight flutter on the boost gauge. I think it might be a problem with the electrical side of the wastegates or the recirculation circuit. I have not had a chance to really trouble shoot it myself but I did bring it to the stealership before the extended warranty ran out. Of course those idiots couldn't find anything wrong and said it was my plugs and they could change them for $300. When I pointed out that I had changed them less than 10k ago he stammered a lot and didn't know what to tell me.

If this sounds like what you have it might be something to look at.

 

I'm ignorant of the eco. But, maybe check the compression?

 

I bit the bullet and bought new plugs and gapped them down to .30. Much better get an occasional pop on the 1 to 2 shift but its rare and not very noticeable may just be the exhaust. One looks as to it may of been defective from the start.

 

I drilled my cac back at around 110,000 miles. There is an oily film on the lower splash guard so it is doing its job. Do you think it be worth pulling the pipes and cleaning it out? I still have a slight shudder at highway speeds when I vary the gas pedal ever so slightly. Also does it with the cruise set when it maintains speed. Best way I can describe it is similar to torque converter shudder which it very well may be that.

 

Nick, did you ever solve your random mis-fire issue? I have what I believe to be the same issue on my 2011 f150 EcoBoost.

 

EDIT: This forum software showing multiple threads on one screen has lead to yet another post going into the wrong thread.

 

Mine had the buck when gassing it from a dead stop, turned out to be the "F150 bump" This is an easy fix, you need to buy the part from a dealer or even on Amazon. Here is a video that should help. This is the one piece drive shaft but it is very similar with the two piece shaft.

.

Here is the part from Amazon.

Ford KIT Drive Shaft Boot Repair... .

Joseph

 

My truck has the misfire code. When it's hot out side I get all the problem lack of power, bad acceleration, bad idle. Flashing engine light. It will usually clear up after about 15-20 minutes of driving.
I have the P0304 code. Refers to Cylinder 4. Usual causes, Bad plug, bad coil or fuel injector. I've replaced all the plugs. I do regularly around every 40k mls. I replaced the coil. Even changed the canister purge valve. I drilled a 1/16" hole in the inter cooler. I did the coil & inter cooler last night. Didn't drive it anywhere but I did let it idle for about 15 minutes. It seemed to idle pretty smooth. Even reved it up. Seems ok. When I read about drilling a hole ,I thought about the catch can idea. I would think the catch can is suppose to keep all oil from entering the inter cooler. So, when I drilled my hole, I did get oil from it. I thought I get a lot more since I have 230650k mls on it. I saw videos with a lot less miles and a lot more oil come out. BTW, I did change a CAT before all this since I had that code too. This truck is killing me...
Anyway, I read about a year ago about the intercooler. My truck displayed those symptoms, loss of power, poor acceleration. I read that high humidity causes this. It's high over here in texas. I think my biggest question is now is. If I replace the intercooler with a high performance one would I still need to do a catch can? Or, do I just do a catch can? Would be cheaper. .But some of these dealers recommend changing the intercooler with a high performance one because they know this humidity issue causes this problem. They also recommend not going back to a OEM brand since it doesn't perform as needed.
Could use some input. Getting really tired of this!!