98 caravan - 2 issues at once

abrad

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#1
Don't know why, but I have a feeling this is gonna end up costing. . .
98 Dodge Caravan, 3. 3, 4 speed automatic trans, 153,000 miles. . .
Just popped an OBD code 0304 - misfire #4 plug. It started stumbling (a little) yesterday, was a bit recalcitrant this morning (Okay, it WAS 5 degrees fahrenheit, so who isn't grumpy about going out?), then really started stumbling on the way home (and no, I didn't stop for a drink!), before finally throwing the code after an evening store run. I have not yet had a chance to check the plug, wire, etc yet (need to clean the garage out so I can squeeze it in), but which one is the #4?

Also, a second problem which just started a couple days ago, but I don't think is related, but will include in case it is one of those compounding problems. When shifting into gear, sometimes does not engage (reverse and/or drive), especially first thing when starting out. Have also noticed a few times that it seems to be slipping on occasion, similar to driving on an icy patch of road where you have alternating strips of ice and dry pavement. I am now wondering if this could just have been the beginning of the #4 misfire??? However, tranny fluid aint quite so red anymore (more like a brownish red, which has not been changed in quite awhile).

Any ideas, pointers, etc will be greatly appreciated as I prepare to get my hands dirty.
Thanks for all the help
 
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#2
It might just need a tuneup...I would fix the P0304 and see if you still have other issues...maybe change tranny fluid and filter.#4 is the middle wire in the front....Here is a diagram of the firing order....Jim

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abrad

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#3
I was thinking the same thing about the tuneup after I posted. really don't want to go that route if I don't have to, unless you know of an easy way to get to the back plugs without busting up all the knuckles ;)

Thanks for the wiring diagram, and how big of a pain is it to change tranny filter and fluid? That is one area I know next to nothing about, and as this is my daily driver, I don't want to screw it up!!!

Thanks again...
 
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#4
Doing better than my daughter with her 99 Caravan, purchased it new with dealer maintenance, at 90K had that stumbling problem turned out to be a cracked head with coolant leakage, she paid some $3,500.00 to get that repaired, but at 110K her AT started slipping, got an estimate on that and decided to buy a new one instead. Hear about a lot of problems with these mini's at the 100K mile mark, you are doing great?

But would check for coolant leaks, can't say much about the AT, that's Cheefs, and Transman's department. Just know that my Chrysler dealer is bring in AT's by the truckload. About 15 years ago, these mini's had a very high resale value, now they are giving them away if the mileage is over the 80K mark, normally have very nice bodies and interiors, but expect to put in a new engine and AT. Thought about it, but getting too old.
 

abrad

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#5
:mad:
Okay, on the way to work this AM, running pretty rough, check engine started blinking then went solid. Now, in addition to the 304 code, it is also showing 300 & 301. Spoke with a friend who works in the service dept. at the dealership; their first "suggestion" was to swap the plug and see if the problem follows -- not gonna do that, I'll just replace the plug, it's cheap enough...

Did a tuneup around 110k, so another tuneup is not out of the question. My question is, has anybody heard of more than one plag failing at the same time? Or might I be looking in the wrong direction???

Thanks
 
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#6
Spark plugs have a story to tell as how a cylinder has been firing whether a cylinder is running richer or leaner than the others, it's a good sign if they all look the same, but you probably won't find that in a high mileage vehicle. If a plug is blacker than the others, tells you to check the spark plug wire and the injector. Also found plugs that had leaks on the ceramic and even plugs with the same number on it that looked much different than the other plugs in how far the electrodes stuck out. Plugs lasting 100K miles is a fairy tale and if you do leave them in nearly that long, you will never get them out, the boots are baked on with a very hard carbon build up on the exposed threads. I notice a decrease in performance after 25-35K miles, electrodes may be okay, need cleaned with that burnt on carbon inside the center electrode ceramic, and regapped. Still burning carbon in the gas and that still makes a mess.
 

abrad

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#7
Update to my problem -- Following thru on the possibility of it being a spark plug issue, I picked up and replaced one plug (#4) last night and cleared the codes. Today the only code that is setting is 0301, which had started yesterday. The 0300 is not showing (only one cylinder misfire, so it won't be showing the multiple misfires) and neither is the 0304. I am thinking I am on my to this being fixed
Guess what I'm doing this weekend ;D
On that note, I have heard a rumor that there is an easier way for getting to those hidden rear plugs, other than reaching up along the exhaust pipe from underneath like I've done before. The rumor is that you remove the grill cover along the leading edge of the windshield, (gotta remove the wiper armatures first) then remove the upper portion from the top of the firewall area. Supposedly that will open up a big enough area to reach down from the top. Has anybody heard of this before I start tearing things apart?

Thanks again guys
 

abrad

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#8
???
okay, replaced the plugs and wires today, cleared the codes; went out tonight and it is still running rough, then set the 0301 code again. Ant other ideas????
 
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#9
When you had your plugs out, did you do a compression check? Also a good idea to disable the ignition, those zener diodes in the module are never large enough to eat the spark and if that goes, a new module is in order.

Nice when you find a fouled plug, but with high mileage engines, doesn't always work out that way. But if you have good compression, could be EGR or injector problems as well, plus a bunch of other surface type stuff.
 

abrad

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#10
No, I didn't do a compression check - I don't have that piece of equipment. What is the module you are talking about? As for the EGR, I just replaced that within the past year.

None of the plugs looked fouled, so I am baffled as to what next. I do plan on checking all connections again, just to make sure everything is seated tight.

What is the procedure for checking injectors? As this is my daily driver, I don't have much opportunity to work on it, except for weekends, and I can't afford to tear it down then find out there is even more work which requires more days out of commision.

Unfortunately, diagnostics was never a forte of mine, which is why I search this site and the internet for answers. Plus, I have a couple of friends who do alot of wrenching themselves, so I have enough people to ask around and get opinions.
 

abrad

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#11
fixed fixed fixed

Went back at yesterday, pulled the wiper tub so I could access #1 from a better(?) angle, and it turns out I did not have the plug wire entirely seated. Gave it a push from above and it dropped about 1/16th of an inch, and made a nice little click when it did. Cleared the code, again, and took it for a drive with zero miss.

Thanks again for all the info...