OK HANK HERE'S THE DEAL. LAST NIGHT MY BEST FRIEND WHO IS A MECHANIC AND SERVICE MANAGER AT A DODGE DEALERSHIP CLEANED AND SWITCHED THE #5 & #1 INJECTORS TO SEE IF THE MISFIRE CODE WOULD FOLLOW THE INJECTOR. WELL IT WASN'T THE INJECTOR BECAUSE THE CODE CAME ON THIS AM DURING WARMUP. NOW THE INTERESTING THING ABOUT THIS SITUATION IS WHEN I FIRST GOT THE TRUCK IT WOULD STUMBLE FOR ABOUT 10-15 SECONDS AFTER A MINUTE INTO WARMUP. ONE OF THE MEMBERS AT THIS SITE SUGGESTED CHANGING THE IAC VALVE WHICH I DID HOWEVER THE PROBLEM PERSISTED. IT DID NOT THROW ANY CEL'S SO I DIDN'T WORRY ABOUT IT. MY BUDDY SUGGESTED CHANGING THE INTAKE GASKET AND SOME TYPE OF GASKET THAT SEALS THE INTAKE MANIFOLD ON THE BOTTOM WHERE IT SITS ON THE ENGINE. HE SAID THAT THIS CAN CAUSE THIS PROBLEM AS WELL WITH THE DISTRIBUTOR TO BE LAST DUE TO COST. I DID LOOK INSIDE THE T.B AND DID SEE SOME OIL DOWN IN THIS PAN WHICH SOMEONE SAID THAT MEANS IT (THE GASKET)NEEDS TO BE CHANGED. ONCE I CLEAR THE CODE THEN THE CEL STAYS OFF DURING THE REST OF THE DRIVE AND IT ONLY COMES ON DURING WARMUP AFTER THE TRUCK HAS SAT AND COOLED DOWN. THERE IS A DEFINITE "LOPE" TO THE IDLE AS IF IT HAS A MISS. WELL HANK THERE YOU HAVE IT WHAT DO YOU THINK? THANKS FOR THE HELP.

 

Switching the injector was a good idea to narrow down the problem.
For the same reasons switching one of the other ignition wires over to #5 ought to be done.

Now it would seem the most likely reasons would either be:

1. There is a break or bad connection in the wiring to the #5 injector or the electronics in the PCM computer that handles that injector is bad.

2. The #5 cylinder has a bad crack/ring seal/leaking head gasket and has very low compression, lots of wet coolant, or lots of oil

 

HOW WOULD I REPAIR THAT IF THAT IS THE SITUATION? ALSO MY BUDDY SAID I MIGHT BNEED ANOTHER DISTRIBUTOR WHERE WOULD I GET ONE OF THOSE AND HOW MUCH?

 

ALSO HANK HOW WOULD I KNOW THE PCM WIRING FOR #5 INJECTOR IS BAD? AND IF SO WOULD I HAVE TO REPLACE THE ENTIRE PCM? THE CYLINDER IS FINE BECAUSE I PULLED THE PLUG THINKING IT WAS BAD , EVEN THOUGH I JUST INSTALLED THEM 1000 MILES AGO AND THEY ARE THE IRIDIUM PLUGS, BUT IT WAS FINE AND NO OIL ON IT OR AROUND IT. I DON'T KNOW IF THAT WOULD BE A GOOD INDICATOR THAT THE CYLINDER IS OK BUT THERE WAS DEFINITELY NO FLUID OF ANY TYPE ON THE PLUG AND THE PLUG LOOKED GREAT. HOW WOULD I KNOW IF THE PLUG TO THE INJECTOR WAS BAD? THANKS AGAIN.

 

You need a 1998 wiring diagram or 1996-2001 Ram Field Service manual to check the wires from PCM to injector with an ohm meter.

Here is one that Dodge posted online for 2004 but I don't know if the wiring is similar for your 1998 model year...kinda doubtful:

http://www.dodge.com/bodybuilder/2004/dr/drmiscmo.pdf

You can also buy a $19 'noid light' from an auto parts store like Pep Boys that you plug into the injector wiring plug and watch the light blink in rhythm if all is correct to that injector.

If the PCM is bad internally I do not know of anyone who repairs them and it would have to be replaced.

If the sparkplugs are new I would suspect one has gone bad...which can be diagnosed by swapping it to another cylinder and seeing if the misfire follows it to that cylinder.