Rough idle, misfires and no power when engine warms up.

[PNWRanger]

First off, hello all and thank you for such a great forum! I've ran into a problem with my 2011 4.0L today that ended up leaving me stranded about 10 miles from home.

Misfires on cylinder 1,2,3 and complete lack of power that gets worse with the duration of drive time/ heat soaking. There is a rotten egg smell as well. The problem will go away once the truck cools down but will come back again and get worse until I can't go over 40mph. No other faults are stored. I replaced the coil pack today because of the association of the problem with ambient engine heat. No improvements have been made, sadly. The odometer sits at 113,000 miles with a fresh tuneup using factory parts at 100,000 miles including a fuel filter. Fuel pressure was checked and noted to be running at 65 PSI at idle and on throttle. I checked charging voltage and AC voltage and found no problem. I don't believe it to be an issue with the cat as the problem doesn't exist on a cold engine. This leads me to suspect its a grounding issue that's interfering with the PCM.
After I was able to limp the truck home tonight, I was snapping the throttle and found the speedometer needle bouncing up to 10mph while I was parked and a warning chime would play. I was able to bounce the speedometer needle repeatedly by revving the engine above 4K in my driveway. With the key on, engine off and all accessories off, I can hear a faint electrical buzzing/ crackling noise coming from within the dash near the passenger area... I'm going to try hard reset on the truck tonight but was wondering if there have been known issues with PCM grounds or anything related like this?

 

[Denisefwd93]

Blocked cat converter ... Just guessing

 

[Marty'70]

Blocked cat converter ... Just guessing

X 2 here


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[adsm08]

Yup, sounds like you lost a cat.

You can take the upstream O2 sensor out and see if that helps. If it does there is a definite restriction.

 

[PNWRanger]

Reconnected the battery this morning and started the truck up. Truck idled fine as I gave it a few minutes to relearn. I took it out onto the road and had good power through the gears for a few minutes and then it started losing power again fast. If it was the cat, wouldn't this prevent the truck to regain power again after cooling down?

 

[Denisefwd93]

You don't believe what three people have suggested...

I have experienced the same scenario you are describing. I didn't believe it either, I had a new catalytic converter on my collector car. I drove it less than 5000 miles a year. The element inside cracked and turned sideways.

 

[PNWRanger]

Thanks for that! Will be pulling the cat for inspection

 

[Denisefwd93]

There are other ways to check it without taking it out ADSM suggested 1 way

 

[PNWRanger]

Pulled O2sensor for bank 1 cat and found element quite loose within housing and most likely in pieces. Thanks for your helpful guidance fellas! I'm surprised how the cat created these symptoms. Whats the story with these units? I replaced the passenger one after it threw a CEL just after 80K miles and the truck has had impeccable preventative service work done.

I definitely like the fit and finish of the OEM cats but am wondering if anyone has had good input on the aftermarket units.

 

[Denisefwd93]

There are all types of cats in the aftermarket, the hardest part is finding one that will fit where yours go. The older Rangers fortunately, have them downstream of the y-pipe.

Your truck doesn't owe you anything especially your cat converters, you got over a hundred thousand miles on them. People just don't check them and they really do go bad. I've been through hell with the damn things on other vehicles.

 

[PNWRanger]

That’s a rational way to put it. I can’t imagine what people are going to be getting drug through with maintenance once the new Rangers with that eco-boost engine hits the same mark in service life. I can’t imagine a turbocharged 4 cylinder crawling and lugging around all day in 4-low in Death Valley to be one of its stronger points.

Anyways, thanks again for your time! ?