I have a 2002 Grand Caravan Sport and am getting a p0305 misfire code. Would it be best to just replace plugs and wires and see what happens from there? Van has 140K miles, don't recall the last time plugs were changed, but it has definitely been a long, long time. It looks like it will be very difficult to access the rear plugs, any ideas on the best way to do that?

 

Do your plugs and wires both. Take off the air cleaner and you can reach around both ends of the engine to be able to get to them all in the back. 4 inch and 6 inch extensions and the socket will work fine.

 

Replaced plugs and wires last night, still have the p0305. Cleared the code with the obd II tool, but van still runs rough. What is most likely culprit now?

 

Do yu know anything about wiring or doing a compression test?

 

I can work my way around wiring if I have appropriate diagrams (either schematics or current flow). Don't have tools for compression test (lots of almost everything else, just not that).

 

You can rent one from a parts store. Screw it in the plug hole. Pull the ASD relay and crank the engine. Compare it with another cylinder.

 

My wife didn't want to wait any longer, so it went to the dealer today. Turns out (even though plugs needed replacing) that there was some issue with the coil driver, and they had to reprogram at a cost of $400. Does that make sense, or would replacing the coil pack alone be enough? I know that there is a lot of stuff that happens with the PCM, but it seems strange that it would suddenly decide to randomly not send a signal to one cylinder to provide spark.

 

There's no way to program a PCM and make something like a coil driver work that didn't work before. Just doesn't happen. I have my suspicions your injector harness wiring is starting to melt together. Here's what to do. On the right side of the engine ,,,facing the car..there is a 10 way connector behind the coil. Unplug it, peel back the velcro wrap and see if those wires are stuck together. Sorry I dont have a pic.

 

Coil pack was replaced and that solved the issue. Still seems kind of expensive, but I it is what it is. If you assume double the cost of purchasing from an AutoZone or like store, coil pack would be about $130, an hour of labor to install @ $125, another hour for diagnosis @ $125, that puts me @ $380 + tax, right at what we paid. I guess I am a little miffed about the diagnosis charge, as I was able to tell them the code, that there was gas going to #5 cylinder, so the issue would be spark, and new plugs and wires would eliminate those variables. Se la vie...

 

I read the reply to the 10 pin plug. Is this usually the problem? I have a 2001 with the 3.3 ltr & 205K miles. Throwing code PO204 & PO 304. How do I check the voltage @ the injector plug?