I bought the 98 durango w/5.9 and goodies that were mentioned on an earlier thread. Everything is great and the power is somewhat impressive however within the last day the check engine light came on. It says P0305 (5 cyl misfire). It is now idling a little rough but that goes away even if reved to just bellow 1000 rpm so I believe that it is just one cylinder as is indicated by the code. I switched the spark plug out from #5 and got the error code again. I switched the #7 and 5 plug wires for each other to see if I would get a po307 code and indicate a bad wire but again I get the 305 code. It seems I've ruled out the plug and wire. Any suggestions as to where to go from here? I'm thinking bad injector but it seems with these engines it could be anything from a weak battery to voodoo. Let me know your thoughts. I'm the kind that would rather spend a few days trouble shooting than spending big cash at the service.
Tonight I erased the pending PO305 code and reset the PCM completely. Tomorow I'll check out the dist cap/rotor but I don't expect to find anything there.
The rig runs fine at anything over 1000 rpm so it's drivable right now [>:]and this problem wasn't there when I bought it. There were not any pending codes whatsoever.
It has accell coil and wires, K&N CAI, mopar headers, Borla Cat back, 60,000 miles.

Any help would be appreciated.

Lee

 

It may have to do with the spray pattern of the injector, all it takes is a slightly dirty injector to throw off the spray pattern causing a misfire on the cylinder. If it were me I would try to swap the #5 injector with one of the others and see if it is still the same cylinder acting up or if the problem follows the injector. If it is the ijector you could then either replace it or try to use a decent fuel system cleaner.

 

I wonder if I can do that without replacing the injector seals, or should I pick some up?

 

I would replace them for permanent use, but I'm sure you could get by with using the old seals for testing purposes.

 

Update.
Switched out the Bosch platinum2 plugs that were in her and put a set of Champion 4071 as has been recommended here before and she runs even rougher. Pulled them out and rechecked the gap but still the same thing. Should a master reset be done on the computer after a plug change?
Can anyone explain their thinking on the platinum 2 or 4 vs: the Champion 4071's. Seems that in my case the claims don't make sense. Perhaps once my misfire issue is resolved I will see some evidence of the 4071 claims.
As for further troubleshooting it seems that the P0305 code is correct because I checked the header temps at each exhaust port with an IR gun and at start up the #5 cylinder is @200 whereas the other cylinders ar closer to 400 degrees.
I picked up a couple sets of injector seals and will do the injector swap thing tomorow as outdoor light becomes scarce here at 4:30 pm.
One thing of note is that there has always been a noise coming from the header on the #5 side of the engine that was thought to be a header gasket leak but I'm thinking now that it may be a valve spring problem. That could also be my #5 misfire problem. Anyway one thing at a time. If I find that #5 misfires with an injector swap then I'll have more direction.


Any other thoughts or experiences out there?


Lee

 

You never said anything about a sound [sm=chairshot.gif] Do a compression check to start. You probably have a cracked exhaust seat keeping the valve open on compression stroke. Or a bad head gasket. Or a bad injector. We can go on and on.

 

Does the Durango run rough all the time or is it weather related? (only happens when wet out)

I got the misfire on #5 code on my 98 with the 5.2L. I changed the distributor cap & rotor and it ran a lot better, but it would still throw the code when it was really wet out. I then found a heater hose running over the distributor was getting really close to the sparkplug wires near the firewall, once the hose was tied down (away from the wires) the code has not reappeared and the Durango has been running smoothly since.

 

I've only had the truck for a little over a week and the problem started a couple days after getting it. the temps and humidity have not changed around here. I don't see what a heater hose would do to the plug wires. I'm running accel 9000 extreme temp wires due to the headers that are installed.

 

Did a compresiion test today and found all cylinders to be at 165 psi except for #7 and #5 which were both lower 140 and 130 respectively. I'm now thinking that the problem is a blown head gasket due to 5 and 7 being low while all others being dead even. Would a leak down test tell me more? I just did a regular compression test.
BTW is 165 a little high anyway? I notice that the haynes manual states 100 psi to be acceptable with no more than 40 variation between cylinders.

I think this might also explain the noise coming from what was thought to be the driver side header.

Just did an oil change a couple days ago and didn't notice anything unusual about the old oil, and coolant looks to be free of oil too. Is it possible that the head gasket has not been breached between the oil and cooling sytem but at the edge of the cylinders allowing compression to be lost only?

Vac checks out perfect at 21 inches with dead steady guage.

Are there any snake oil additives that can be put in the engine or cooling system to maybe fix the problem without a head removal?


Lee

 

didn't notice anything about plug wires in thread (i didn't read everything though so sorry if its a repost). I had a misfire in #7, replace wires 45 bucks and all is fine now.