i have a 99 ram 1500 thay i recently put new plugs and wires in. about a week after i ran seafoam through the brake booster line and in the gas. shortly after it started stumbling a little and the check engine light came on. i thought i might have clogged up the 02 sensor but when we plugged the computer to it it showed a #5 misfire. i checked all the wires and connections and pulled out the #5 plug and it was clean but it didnt smell like gas or anything so i thought it might be a clogged injector. any ideas. .

 

First double check you have the wires on the distributor routed in the correct firing order, which is listed on the front if the intake manifold.

If that doesn't help, follow this TSB on wire routing:
http://dodgeram.info/tsb/1998/18-48-98/18-48-98-v8.htm
If that doesn't fix it, repost and we'll try something else.

 

some claim you must run the 5 wireat a 90 degree angle to the seven

 

oh forgot to mention its the 3.9 not the v8

 

Then that might be a clogged catalytic converter issue.

 

Hey there. Dont know if the 3.9 has the same syndrome as the 5.2/5.9 but I had the same issue for a while. I replaced all the normal tune up stuff (plugs, wires, cap, rotor, injector, etc). Turns out the issue became more and more noticeable, and it ended up being a burned #5 exhaust valve.

New set of Heads fixed the problem right up.