Engine backfire and missing

05 RC with 26k miles

So lately I’ve been noticing that at random times my engine will misfire and or backfire when driving. First time it happened it was right after I fully filled the tank. I was lightly accelerating on an entrance ramp to the interstate and it was bucking like crazy. I tried to keep it running but would miss and backfire. So I let it die and pulled over onto the shoulder. Turned the key off and then restarted it. Seemed fine so I took off again, same thing at about 3k rpm but the lighter with the throttle I went the less it happened. Milked it home a few miles but got on it hard on my street and it was like nothing happened, all better....so I thought. As time went on I was cautious driving thinking it would happen again. I thought maybe a one way valve at the fuel neck may have gotten gummed up from filling the tank and not allowing it vent to atmosphere but....

The second time it happened was at about half tank, this time it happened at light throttle just cruising with rpm at about 2k. I let it die and while still rolling restarted it and kept driving. Didn’t happen again during that short trip and also made it back home with no issue. No codes have been thrown yet about any misfire and it’s getting frustrating. I do however have a emission evac small leak code (probably from a hose somewhere) but checked all of what I can get to for leaks. Even replaced the gas cap and had the code cleared but no dice, it came back after 40 miles or so.

Now it happens randomly and can’t pin point anything that may lead me to investigate further. I just recently replaced the spark plugs Andy the old ones looked great and no change. Injector cleaner? Seafoam? Coils / wire?

What’s everyone think?

I remember mine was doing this a few weeks before it lost power completely, and it was a bad Cat

At 26K you shouldn’t have any issues with coils but it’s possible. Start with the spark plugs and wires and work your way back to the coils. A fuel treatment wouldn’t hurt either, especially if your truck isn’t driven very often.

Could be a few things, Bad injector or your TPS could be going out. Mine would stall out like that and it turn out to be the TPS

No CEL is hard to diagnose, especially over a keyboard

Thanks for the responses guys, I’m gonna start with injector cleaner since it doesn’t get driven daily and I just replaced the plugs. After that I’ll replace the wires and it looks like I’ll have to remove the intake to get them off so I’ll probably do a proper catch can set up and suck out any oil that’s accumulated in there while it’s off.

Jumpingjoe628 said:

Thanks for the responses guys, I’m gonna start with injector cleaner since it doesn’t get driven daily and I just replaced the plugs. After that I’ll replace the wires and it looks like I’ll have to remove the intake to get them off so I’ll probably do a proper catch can set up and suck out any oil that’s accumulated in there while it’s off.

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Clean the throttle body mate, it could be hanging up? My SRT8 Jeep has a habit of that, and the 10 did it a few times in the past.

thewelshm

Silver05 said:

I remember mine was doing this a few weeks before it lost power completely, and it was a bad Cat

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I'd head this advise. Sounds like a Cat that has become dislodged internally. Get underneath and see if you can bang on the cats. If one rattles, the honeycomb platinum substrate has broke loose. This causes a "clog" upon high exhaust flow (more throttle).
Happened exactly as you described to my 1996 V8 Dakota.

Good Luck! Cheers!

Psycho1122 said:

I'd head this advise. Sounds like a Cat that has become dislodged internally. Get underneath and see if you can bang on the cats. If one rattles, the honeycomb platinum substrate has broke loose. This causes a "clog" upon high exhaust flow (more throttle).
Happened exactly as you described to my 1996 V8 Dakota.

Good Luck! Cheers!

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My cats are under the workbench in the garage

Be a good excuse to de cat maybe:dontknow:

I’m all for de-catting, as when I got the truck the rears were already deleted. So now since my knowledge with modern tech computers and what they control on these newer vehicles is limited (always had older hot rods), how will the sensors react when the cats are removed? The front sensor before the cat shouldn’t be a problem but the post cat sensor will likely not detect properly and probably throw a code. Is there some sort of delete attachment to plug into the wire instead of using the sensor itself so as not to throw a code. It’s not like we have emissions testing here but I really don’t wanna see the CEL lit on the dash if I can help it.

Jumpingjoe628 said:

I’m all for de-catting, as when I got the truck the rears were already deleted. So now since my knowledge with modern tech computers and what they control on these newer vehicles is limited (always had older hot rods), how will the sensors react when the cats are removed? The front sensor before the cat shouldn’t be a problem but the post cat sensor will likely not detect properly and probably throw a code. Is there some sort of delete attachment to plug into the wire instead of using the sensor itself so as not to throw a code. It’s not like we have emissions testing here but I really don’t wanna see the CEL lit on the dash if I can help it.

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You can purchase simulators that will trick your computer into thinking there is proper working cats on the vehicle.

I got these from the viper store which were a little pricey but worked like a charm and had no clearance issues:

Part # O2-SIMS-90X2
Dodge RAM SRT-10 (2004-06) Performance exhaust CAT O-2 '90° LOW Profile' Simulator-Spacer - Stainless Steel. For tight spaces.
https://theviperstore.com/RAM-SRT10_Products_Performance_Exhaust.htm

Again, at 26K I highly highly doubt it’s a cat but it’s possible. I would start simple first then go balls deep on the issue.

Psycho1122 said:

I'd head this advise. Sounds like a Cat that has become dislodged internally. Get underneath and see if you can bang on the cats. If one rattles, the honeycomb platinum substrate has broke loose. This causes a "clog" upon high exhaust flow (more throttle).
Happened exactly as you described to my 1996 V8 Dakota.

Good Luck! Cheers!

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This happened to my buddy in his Crx

Took the cat out and found out it had turned into a little ball that was rolling around sometimes blocking exhaust flow

Kx

So looking at this from a logical prospective, they are simply spacers that move the sensor up and out of the exhaust path. And it appears from the description that it is heat sensitive only? But my issue with the description is that it states that the exhaust gas temps will increase higher when removing the cats? How is this possible when the function of the cats is to heat up during a chemical reaction by the elements it’s made from to help burn off unburnt fuel? ie the cats outlet would be hotter than if having a straight pipe. So then removing the cats would have a lower exhaust temp and if a spacer was installed it’d be even lower.

I also thought that these sensors read the gasses content as well, that obviously can’t be the case if these spacer would fix the CEL when completely removing the cats. If it works then it works, but I’ve already seen them on eBay for $10-12

QUICK UPDATE*****

On the way to Advanced Auto to purchase some injector cleaner it happened again, this time stranded me in the center lane median for a few minutes as it wouldn’t immediately start back up. After a few attempts it finally started. While at the store I got an OBD2 reader since this time it tripped the CEL. Turns out there’s a couple codes. P0320 for “crankshaft position sensor circuit” and P1391 for “loss of camshaft crankshaft”. What also popped up was my Evap codes “medium” and “gross” leaks that I’ve been trying to track down.

Got it home safely and dumped the can of Seafoam brand injector cleaner and let her idle a few minutes while I pulled the codes myself on my new toy. Then I erased them and took a spin around the block. Got on it a few times and it’s runs great like nothings wrong. Could this just be a faulty sensor or better yet a loose connection on the harness? Or is it something more involved?

Ok, bought a new crank position sensor and went out in the rain to change it. Not too bad to get to from underneath. Wow!!! What a difference when I started it up! Came to life instantly and had a waaaaay smoother idle. Also had crisper throttle response when revving. Gonna giver her a shake down run tomorrow during daylight time.

Before as it idled it sounded like an exhaust pipe or muffler leak and would also excessively backfire and crackle on decel. Even during free revving. Almost non existent now. Unfortunately it’ll be raining till Monday here so won’t have dry ground to see if any performance is restored but it felt great to begin with while this issue was present. Will update the thread if any more codes come in related to this and for a test drive update. Thanks y’all for the help!

Atleast you got a cel now, you can start tracking it down, my truck popped, misfired and lost power , and kicked my dipstick out and blew oil all over

Silver05 said:

Atleast you got a cel now, you can start tracking it down, my truck popped, misfired and lost power , and kicked my dipstick out and blew oil all over

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Think I read in another thread that it was a clogged cat right? Causing back pressure? I could be wrong but after all the different threads I read last night (at least 50) they are all kinda blurring together, lol.

I’ve identified my cats as a 2.5â€￾ Maganaflow universal part from the serial numbers on them. The rear cats have a short test pipe welded inline and then each side goes to magnaflow mufflers. I’m glad they’re not the originals as some have suggested that they can break down and clog due to the poor design.

So after my morning coffee I’ll be taking her for an “errandâ€￾ run to see if the issue returns and we will see.

Keep in mind , my 05 only had 55k when the cats went bad , cost me $1000 to replace 1 when I had the cat delete system and the dealer would not install them for me

Test drive was good, now only time will tell.