It started out as code "P0305",# 5 cylinder misfire,wires were original,as were the cap and rotor.I tuned it up with Accel cap and rotor kit,Taylor 8mm wire set,Bosch platinum plugs.I cleared codes with scan tool,took out for a test drive,had no guts and engine shuddered badly and check engine light was blinking before it finally set.Hooked up scan tool to find code "P0303" #3 cylinder misfire,switched plugs from #1 to #3 to see if code goes to #1 cylinder,it did not.Switched wires from #1 to #3 it still reads #3 misfire.Changed cap and rotor with Borg Warner parts,cleared codes,went on test drive,same results,no guts what so-ever,engine shuddered badly,blinking light,then finally set.Itthen read "P0304" #4 misfire,so just for kicks,I changed the wires with Autolite pro series,and put in Autolite plugs,cleared codes,test drove,same results,no power at all,engine shuddered badly,blinking light,finally set,.Now it reads "P0300" misfire various cylinders. Any ideas ? . I have heard to replace injectors,replace pcm,plugged cat,I pick up no other codes other than misfire codes,scan tool says all else is o.k.Lets go back to the state it was in before tune-up.This thing ran like a raped ape,all kinds of power,nice burn-outs,etc. Truck is equipped with K&N filter,hi-flow injectors,magna-flow cat back duals,shift kitted trans.Never had any problems what-so-ever until tune-up. Vehicle is a 2000 Ram 1500 ext.cab, 4x4 , 5.9 mag. 70.359 miles. I am lost,I need found, L.O.L.

 

take it to a muffler shop and have the cat pressure tested. and like you said check your injectors, trashy gas can give you clogged injectors that can cause a mis. also check the routing of the wires, if they cross each other or touch some will miss.

 

cat checked out o.k. . took out injectors,took to a place which does flow bench testing on injectors,they checked o.k. ,wires are not touching anything,and are secured in loom holders. I have always run Marathon fuel and never had a single problem with gas,not to say you cannot get a bad batch,but it is kind of strange it only started after tune-up,any more ideas ????

 

SOLVED PROBLEM !!!!! Bad wires , it took 3 sets of wires , but that was the problem. Hope this helps any-body else. I would recommend doing an ohms check on new wires before installing them,you should not have to do this,but let it be a learning curve,it could save a few hairs on your head