Are there other owners who have had a major cylinder misfire (flashing engine code) due to fouled spark plugs BEFORE the 102,000 recommended Tune-up maintenance where the spark plugs and wires are recommended to be replaced? I had an engine light come on and start flashing, engine shaking, and loss of power within a few miles. I had my 2008 DGC (at 98,000 miles)(3.8L) towed to the dealership, where they told me my spark plugs were fouled up bad enough that it caused a misfire. I was trying to wait until my DGC hit 100,000 miles before doing the tune-up (replace spark plugs and wires)(note that would be 2,000 miles BEFORE my maintenance book recommended they be replaced). But apparently that was a BAD idea. If I can't trust the maintenance schedule put out by Dodge, when should I replace the plugs and wires next time?

 

Depends on how well you maintain your vehicle.

 

When you say maintain, what specifically are you referring to ? I have done all the recommended maintenance on my DGC, according to the owner's manual. I have always had it serviced at the same dealership since I purchased it brand new there. What could I have missed?

 

Fouling plugs could be caused by bad gas too. If you have the dealership do all your recommended maintenance then that would rule out lack of maintenance. Did you by chance ask their opinion?

 

I did, and the service advisor told me "its just something that happens". His advice was as "clear as mud". :/

 

Iridium plugs are the only ones that do 100k. Platinum around 50k, copper around 30k I think..

I get Champion or Denso TT Iridium from whoever are selling the lowest, set gap, and forget unless something happens..

FYI plugs and coil are directly connected to PCM, PCM controls timing. If you have a problem it's probably mechanical timing vs. PCM timing, or a type of leak.

 

Er well, I've had plats last well over 100K. I still have the original plug wires at 214K miles and she runs like a top.

Spark plug fouling can have many causes and the published maintenance interval is hardly an exact science. Many have problems in spite of a pristine maintenance record. If it's made by man it will break regardless of what's printed in a book.

 

All the manufacturers spec iridium at 2x single and double platinum. I also leave plug wires unless something happens, I think I've gotten 250k before just swapping them on various vehicles for preventive maintenance or selling.

To me it's all about value. I'll spend $3.00 extra on something more durable. I'll do single platinum at least if I'm tight on money and need some, but really shoot for iridium even if I have to order from the net.

 

You may be on to something here! I looked back at the paperwork from the dealership, and read through the tech's notes again. The notes on the invoice read as such - Page 1 notes : "vehicle came in with dtc p0300 and p2308 set ( coil 3 circuit insufficient ionization, multiple cylinder misfires ). vehicle was misfiring due to a bad #3 ignition coil and bad #1 spark plug. all 6 spark plugs replaced as well as all 6 ignition coils. dtcs were cleared and vehicle test driven to verify repair.
Page 2 notes : vehicle came in with a check engine light condition, after being determined that the spark plugs were the issue, they were replaced. after the new spark plugs were installed, the vehicle still misfired at cylinders 1 and 3. ignition wires were swapped but the misfires remained at cylinders 1 and 3. next the spark plugs were swapped with cylinders 2 and 4, vehicle was started and by now the misfires moved to cylinders 1 and 4. both spark plugs were removed and inspected for any cracks or damage but they seemed fine, the gap was check as well but it was within spec indicating the spark plugs were faulty. two new spark plugs were installed and the vehicle started, no dtcs came back or misfires came back and vehicle ran smoothly."
I know all six plug wires were replaced as well (because I asked to get all my old spark plugs and wires back).

I know the dealership had my vehicle for a week. The service advisor told me that the spark plug caused the problem. But after reading through the notes again, I have to wonder what the real problem was that started this? Was it really a fouled spark plug? (hmmm...the chicken and egg dilemma).

 

There are no individual coils, it's one unit with 6 coils inside a molded plastic non-serviceable enclosure that you just bolt on and connect on top by the manifold. It's been that way since 2nd gen.

For what you paid in just trial&error labor you could of replaced all plugs with iridium Denso TT or Champion, all wires with Champion silicon, and the coil from a parts house, and these are easy to install. Except maybe the rear plugs which you have to take the wiper tray off to reach, but a few hours labor requiring no skill.

But yeah, that coil pack by the manifold connects directly to the computer by the battery. The same deal with the injector harness which could possibly be causing the problem too. Injector harnesses on these vans are famous for melting and shorting and causing P0601 eventually. The solution for those is rebuilding the harness with better grade wire or buying another and placing it better.