Hello everyone, I am new here and was hoping I could get your help with a Ram I am trying to help a friend fix.

It is a 1998 Ram 1500, with the 5.9. I am getting a cylinder 8 misfire code, and a definite miss in the motor. I have already checked spark, replaced spark plug, checked injector wiring, etc... It still misses. Someone told me today it probably has a cracked head at the exhaust seats, could this really be? Any help or ideas would be greatly appreciated.

By the way, this seems like a great forum! Thanks fellas.

 

how does the plug look? have you done a compression check? have you checked the Plenum gasket?

 

check the cat to make sure its no clogged up


*** after a full tune up***** edit

 

also check the spark plug wires

 

If they are cracked burnt through or just looking worn, it can't hurt to replace them.

 

or swap with a diff wire and see if you get a different cyl to missfire?? there are lots of threads about missfires, i had number 6 missfire and that spark plug was wore down pretty good,replaced and no more missfire.

 

Hit it with an axe!

 

Thanks for the replies everyone, I do appreciate it! I took a spark plug, and hooked it up the the #8 wire, and it has good spark. I'll change the spark plug, and see what happens. But could it be the fuel injector? And if it is, does anyone know how to change them? Is there anything special about the Dodge injectors? I have changed injectors on Diesels, and a few Ford and Chevy gassers, just not Dodges. Thanks again!

 

If you have good spark, then don't start yanking and swapping injectors. There's a TSB that deals with plug wire routing as well as wrapping the plug wires in convolute. *FOLLOW THAT FIRST* to rule out a misfire cause. Clear the code after having done so, and if the misfire returns, get the exhaust pressure checked to rule out an issue with the cat.

 

And no, I haven't done a compression check yet. I was checking all the easy, and obvious things first. But I will compression test the engine today, and let you guys know what I find. What are considered "good" compression readings for this engine? And what are weak #'s?