Hey all!

So using the key 3x trick I found the code for my 2006 Grand Caravan 3.3L SE that had been running kinda rough a missing every so often (no rhythm). Turned out to be a P0302 code which is a misfire in the #2 cylinder. I pulled the plug wire and plug, and the gap on the plug was 0.054 instead of the recommended 0.050. I'm not experienced enough to know if that much of a difference would throw the code and cause my problems.

Here's my issue though. I just had all the plugs and wires replaced maybe 8000 miles ago, so I'm surprised that this is the issue. Now I am not sure if I need to replace EVERYTHING again, or if I can just toss a new NAPA plug into the #2 cylinder and go on my merry way. Just from playing around in the engine compartment, it seems like changing plugs #2, 4, & 6 are easy. Changing #1, 3, & 5 seem like they need to be done by a Gumby or someone a lot more flexible than me. Or perhaps on a lift. Unfortunately I don't have one at home, so am I pretty much going to have to take this to a mechanic just to do the plugs and wires again?

Any other thoughts on what might be happening?

Thanks!

 

This may help you get to those plugs.
https://dodgeforum.com/forum/dodge-c...ml#post2531517

 

The NAPA plugs may be part of the problem as many have had problems with brands other than Champion. You could also try setting the gap at 0.040.

 

Pull another plug and check it's gap. I have a hunch you'll find the gap close to the .054 of the first plug. Gaps normally grow as plugs wear. Your .054 gap isn't gross. In any case just reset the gap or better yet swap plugs with another cylinder and see if the problem moves.

http://www.obd-codes.com/p0302

 

Deleted double post

 

So I pulled the #2 plug and the #4 plug and swapped them. The #4 plug's gap was actually 0.049. After swapping them and clearing out the P0302, the van is still displaying all the symptoms listed for a P0302 code at http://www.obd-codes.com/p0302. The computer has not yet thrown a code, but the engine still does "stumble and/or hesitate." The engine does start a little hard, but not badly so. Noticing more exhaust smoke than previously and poorer mileage, so perhaps not properly burning fuel? Maybe the fuel injector then? Is that hard to replace?

Any thoughts on what next? Is there any easy way to determine if it is any of the following listed as possible causes?

• Faulty spark plug or wire - Probably not, new 8000 miles ago
• Faulty coil (pack)
• Faulty oxygen sensor(s)
• Faulty fuel injector
• Burned exhaust valve
• Faulty catalytic converter(s)
• Running out of fuel
• Poor compression

BTW - I am not using NAPA plugs. The plugs are all Champion Brand. I mentioned NAPA plugs just because they are easy to find.

 

Wire wise, you can swap #2 with #1 in the back, think they are almost the same length. Yes, you can reach your hand to the rear cylinder cheap, just take out the Air Filter Box and neck.
Coil pack wise, you really just have to throw a new one on and try,
Oxygen sensor would affect all cylinder
Injectors, you just have to swap them, unfortunately.
mechanical problem wise, you just have to use a Compression gauge. Part store might rent you one.

fuel injector is not that hard to get to. You just have to pull off the Upper plastic intake off, then you can get to the fuel rail.

 

I think but not sure if it's a coil problem you would get a p0352 code, I know that's what I got when I had a faulty coil. Like steak59 said you can reach in the back to change the plugs, I didn't even take off the filter box but probably would have been easier if I did.make sure you do one at a time,pulling the wires off is probably the hardest part to do, dam things get stuck on good. I believe they call for double platinum spark plugs but can remember the brand, I herd champion suck but that could be bull.Graham

 

OK. So I replaced the plug wires and the coil pack and there is no noticeable improvement. The engine is still idling rough with intermittent stumble and hesitation. I'm obviously running rich too since my exhaust is noticeable at a temperature when no one else's is. The check engine code has not come back on since I cleared it with my scanner.

As an added symptom, my mileage has dropped to dirt poor, even given that most of the mileage is city driving. Like 11-12 MPG. Used to get 19 MPG city.

So, even though the van threw a P0302 code, could it be the O2 sensor? From the research that I've been doing, it seems like the most likely culprit given the symptoms. Thoughts?

I really appreciate all the help you've all been giving me. It is awesome that communities like this exist. Thank you!

 

The link I sent you stated the O2 sensor can cause a P0302. The tech who wrote that must have his reasons. Personally, I don't understand how a sensor that modifies air/fuel ratios for all six cylinders would cause a a single cylinder to throw a misfire code. I might understand it in the case of a P0300 random misfire code effecting multiple cylinders. Just don't see it causing a P0302. Maybe someone can shed some light on this.

It would be much more likely you have an injector not firing or your loosing compression on that cylinder. You can test injector operation with a noid light, meter, or by just touching it and feel for the click. You'll need a compression test gauge to check for compression. AutoZone is good about letting you sign out test equipment.