At my wits end with my 2005 QC Daytona and now realize why my truck had 5 previous owners. I've had this truck for 2.5 years now and it has been the most unreliable vehicle I have ever owned. On the drive home from the dealer when I bought it with 34K miles, the check engine light came on. That ordeal and troubleshooting took weeks and several trips to a mechanic and the dealer to figure out (well I guess it never totally was) why cylinder 1 was misfiring. All new plugs, new coil pack, new injector, even a new gas pedal and it finally seemed ok. Then an O2 sensor went, no big deal cheap enough to replace. Throttle body was cleaned - wasn't too bad, and the dealer even did a deep soak overnight engine cleaning of some nature to clean out any built up carbon. Seemed to run OK at that point, then it starting having issues with the key not turning. Replaced the internal cylinder which cured it for about a week, then after the problem reappeared, I replaced the entire key assembly. Next the water pump started leaking, so we replaced it. Fast forward to last week and the water pump is now leaking again, we replaced it about 9 months ago, so we got a warranty replacement pump, but this is now the 4th water pump of this truck, what is up with that? When we replaced it 9 months ago, we could tell that unit was not the original, so it's had the original, plus the replacement we pulled off, plus our replacement, now another. Not a good track record.

Since owning the truck, I've installed new shocks all around, some Timbren bump stops to help with towing a travel trailer, a Hellwig sway bar in the rear, and changed the Borla muffler to a shorter Borla muffler for some added tone, also removed the silencer muffler tips and replaced them with identical looking tips with no silencers. Installed a mini cold air intake (Air Raid) and Superchips program. Loved the looks and ride of the truck (when it is running), and all seemed fine until.........

3 weeks ago the darn engine misfire came back and got worse as the days went on. Truck now has 58K miles on it. Initial code said misfire cylinder 1 (here we go again, same cylinder that started all of the problems about 15K miles ago). Checked the plugs and wires and they appeared fine, my mechanic friend and I figured it was a bad coil pack that had been replaced so we replaced it again. Seemed ok for a day, then the cel came back on, said O2 Sensor 1/1, friend seemed to think it was a misfire again so we ran the truck with the scanner on to see how each cylinder was operating. Found out cylinders 3, 5, and 7 were showing misfires, so we replaced the coil packs in each. Ran fine for a day then all hell broke loose. Now all but 2 cylinders are misfiring and the truck runs like crap. Put the old coil packs back in and took the superchips program off and set it back to stock. Also grounded the throttle body. No change, still misfiring with P0300 code but nothing else. We power braked the truck to the point of misfire and moved some wires to see if we had a short, no difference. We also checked the fuel pressure on the rail and it checked good. My mechanic has no clue what is wrong. He thinks maybe a re-flash of the PCM, but doesn't know for sure. Has anybody else had this experience? Can anybody help us figure out what is wrong? No Codes are coming up on the scanner so we are getting no help from the truck. A friend said maybe the cam, crank, or throttle position sensor, but there are no codes for any of those. Also wondering if the harness that powers the coil packs has melted or shorted, gotta check. Ready to light a match........

Please Help!

 

There are certain thresholds for each of those sensors (cam, crank, TPS) that won't always show a failure when there is one present.

I would start by replacing the Cam and Crank sensors, and then I would investigate the timing chain on the engine... It won't be the PCM b/c you had a S/C program on there that would have smoothed out any issues with the OEM programming.

If you are running anything but Copper core plugs I would replace those things ASAP... Some dodge trucks just cannot run on anything but Copper Core plugs... You are also right around the threshold for spark plug replacement if you haven't done it in awhile. (58k-34k = 24k miles)

If the sensors and plugs do not fix it, I am betting that there is something going on with the timing chain, that is causing a misfire as well as incorrect timing.

Let us know how you make out.

 

No progress, several things done thus far:

1. Wires replaced. No change.
2. Coil packs replaced. No change.
3. Plugs inspected, look perfect.
4. Fuel pressure on rail checked. Perfect.
5. O2 sensor 1/1 replaced due to fault code. Code gone now but still have a misfire on 1/3/5/7 cylinder.
6. All harness inspected, wiggled while truck was running. No change.
7. Throttle body inpsected, was clean. No change.
7. Several ground wires were changed or cleaned. Both grounds running from the valve covers to the block were either not connected or loose with bad corrosion. Those grounds were replaced with heavier wire and grounded to alternator stud. 4 other ground wires were cleaned and reconnected. Better at idle but still has a misfire when performing a power braking test, misfire from 1100-1800 rpms or so, above that it's fine, below that it's fine.

To Do:
1. Replace cam sensor and test.
2. Replace crank sensor and test.
3. Bring POS (Dodge truck that is) to the dealer to scan and re-flash or replace PCM.

Any other ideas? Would a bad EGR cause a misfire? Ive read probably not. How about replacement of the throttle body - wonder if any electronic components in the tb went bad?

 

Another update:

1. Replaced cam sensor: no change.
2. Replaced crank sensor: no change.
3. Replaced EGR: no change.
4. Removed positive and negative terminals from battery while I replaced the water pump: ran perfect!........

For 20 miles that is, then cel back on for O2 1/1 sensor (just replaced it!), then all hell broke loose, misfiring again and stumbling along at low speed wanting to stall.

HELP! I'm giving up! What else can it be? Only misfires between 1000-1800 rpm's then clears up beyond that. Why would resetting the pcm work for only 20 miles? All that is left is gas pedal (again ?), throttle body (electronics bad within?) or pcm. Everything else has been replaced. Absolutely aggrivating!

 

Throttle Position Sensor would be my next guess... but it is definitely time to get the dealer to hook up the star scan tool to the truck and see exactly what is going on.... they will be able to get a real-time readout of every single sensor and see what is out of wack....

This type of problem is very hard to pinpoint as so may factors come into play.

You should REPLACE those platinum plugs with copper cores to be 100% sure it isn't those....

the truck runs great after you disconnect the battery because it is running in "learn-mode" which is basically learning all of the sensors and operating condition, so if it learned something bad it will cause a misfire against the base maps that are stored in the PCM memory.....

MAP and/or IAT Sensor can also be causing a problem....

You might have accidentally damaged one of those sensors during the Cold Air Intake install... You might also want to check and make sure nothing is making contact with the inside of the throttle body...

How long after the CAI install did the problem occur?

 

Something that can cause misfires is the catalytic converter. Both my son and I have gone thru misfires that ended up with cat replacements. His was a 03 Dakota with a 3.9 and mine was a 2000 Ram 1500 with a 5.2 Ma has had some problems with cats in the past. You can have your friend put it back on the scanner and then run it with the 1/1 O2 sensor pulled out and left plugged in hanging to the side. It will relieve any backpressure that a plugged cat will cause. Another thing to use is Seafoam. Follow the dirrections and use in the tank. Another thing some people do is have the engine running, unplug you brake booster vac hose and pour about a half can of Seafoam in the vaccum hose a little at a time and then turn off and let sit for about 20 minutes and then fire it back up. The Seafoam will clean out any carbon deposit thru the whole intake and engine system. Good Luck.

 

Check oil for signs of coolant. Those symptoms tell me blown head gasket, coolant in the engine would account for the multiple misfires and coolant being burned into exhaust completely explains the O2 codes...

 

Is it possible you got a load of really bad gas? Happened to me a couple of weeks ago---check engine light and DTC codes galore, engine barely ran until I dumped a couple of bottles of "red" dry gas in. Mileage dropped by 3MPG through the whole tank. Finally ran it nearly all out and filled up with Shell. Everything back to normal

 

I had a coil go bad 2 years ago. It ended up frying the PCM. I could start the truck with pushing the pedal but it was misfiring so bad it could not be driven.

 

Just so you don't feel lonely in your trouble. Two years ago I replace all 8 coil and PCM when truck stopped working no Friday before vacation started. One year ago the starter went out on vacation in Niagara Falls, ON. This year a rod bearing spun on vacation in Michigan. Had the engine rebuilt. Returned home and took the truck to have the u-joints replaced and found the transmission housing cracked. Replaced transmisson, u-joints and center support bearing. Two weeks ago I had the rear differential rebuilt after it started making noise. But your cylinder 1 misfire is a tricky one. Used to be you only had to worry about compression, fuel and spark. We still have the same now but checking the fuel and spark is far more complicated. It will be nice to know what the final outcome is for your truck.