Greetings everyone long time to post. (TRUCK INFO: 1998 RAM 1500 4X4 WITH 5.9L V-8 AUTOMATIC TRANS) I have been rehaunted by my CEL code cyl #5 misfire again. It went away for months however it has recently came back. I pulled the plug and it showed a lean burn pattern and the top of the plug where the plug wire snaps on to it was corroded. When this 1St started happening almost a yr ago you guys gave me a lot of troubleshooting ideas in which i did: resealed the upper intake, changed out cap and rotor and spk plugs, checked compression ( normal ), replaced the fuel pump, changed the injector. I only use chevron, exxon, or shell gasoline and this will happen ever so often but when it does it lasts for anywhere from a week to a month and then it will go away by itself even the CEL will turn off. This latest episode happended when my tank got too low but I have refilled it twice. The " MISS " is definitely noticeable however after driving for a few miles it lightens up. Now my truck does stumbles badly during warmups when the computer is trying to lower the RPM's. I can hear the truck suck in more air when this is occuring to recover and smooth out. This will happen for about 5 minutes then when thr truck is warm it levels out. I know this is long but I just want this to go away. Thanks!

 

After going through the same TS process you are experiencing, the only thing I can suggest is performing a leakdown test on your #5. I finally did this on my #8 and it turned out to be the infamous crack b/t the valve seats. It is fairly common defect with the 5.9L.

 

Pardon my ignorance in this matter, what was your fix? New heads?

 

Hey, I have to agree (as much as it sucks) on the potential on a cracked head. I had the EXACT same situation last year. CEL was #5 misfire, changed out all the external items, etc.

My first leakdown didnt show anything, but I ran it, with the noticeable miss, and tried it again, and #5 was as leaky as I'd seen, like 70lbs lower than the other cylinders.

Long story short, I bent a valve in the process, and every once in a while it would rattle itself around to where it would seat correctly, then when it would miss, it was banging around in there crooked, causing havoc.

I found a set of replacement OEM heads on Ebay for $550, swapped them out and its been smooth sailing since.

Depending on how many miles you have on it, and how beat up they might be, a local cylinder head shop may not even touch them (as in my case). They took them apart, magnafluxed them, and told me they were too far out of spec to even try to grind on.

Good luck!

 

Well since I have been getting this recommendation alot I guess that's the route I'll go. I was sent a website of a company that had heads for these trucks but I forgot what it was. Now that you mention it when I would accelerate heavy at WOT i would hear a slight rattle on the driver side. Well now my question is where do I get new heads that won't require Congress to "BAIL" me out. I have a little over 100k miles on my truck.

 

Look into the simple fix first. Your post said that when the plug wire was removed it was corroded, and the plug looked like it was burning lean and the code was cylinder 5 misfire. Corroded connections in the ignition circuit will cut down the firing ability of the plugs which could be giving you your problem.
Replace the plug wire and plug and make sure the connection is good and tight and that the boot fits snugly. Better to try that than spend a lot of time and money for nothing. If the problem is not solved then you can follow the other suggestions.

 

Well I am going to try that route 1st and see if it fixes the problem. I will repost the results as soon as I'm able to do this. Now I do have an ignition question some one suggested replacing that round pick up coil like thing that is seated below the rotor in the distributor. Suggestions?????

 

Always try the simple things first......like replace the plug wire and plug ,that will probably fix it.....as far as the hall effect switch or pick up coil that you mentioned, you would usually have more than just one cylinder showing bad, since it is responsible for all of them. in a lot oif cases problems with that involve it not starting or back firing

 

The camshaft position sensor has zero to do with the strength of your ignition spark. It's not the problem.

 

Thank you very much. I'll try the simple fix 1st and get back with you guys on Monday. I'll call it " CYLINDER #5 MISFIRE cont. ".