hey so i have a cylinder misfire and it varies which ones they are. i can feel it on the highway it will be like a jerk or stumble. i can clear the codes and it the check engine will come on and it will be different cylinders maybe one the same. i also had fault code p0340. so i have changed the plugs, wires, cap, rotor and camshaft sensor. p0340 went away (camshaft sensor code) but still have misfires. anyone have any idea what this may be? oh i also have a small exhaust leak where my header meets the y pipe flange. would this have anything to do with it?

 

If you can feel it on the highway (faster MPH) then that would lead me to believe you have a clogged cat.

 

hmm i dont think that would be it, i just switched to a magnaflow y pipe and cat less then a year ago. and it doesnt stumble constantly it will do it then maybe a few minutes later, then 15 mins later then like 2 mins later etc

 

Weak spark. Try closing your plug gap .010 and see if it gets better. Since I was thinking this through have you checked your plenum yet?

 

well i added an msd ignition coil, msd plug wires, msd 6a ignition box, and changed the plugs to ngk cold plugs so with the msd i dont think weak spark would be the problem. and nope havent checked it, how would i go about checking it and how hard is it to change?

 

the misfires were previous to adding all those parts and continue afterwards. i also have a superchip, throttle body spacer, high flow y pipe and cat, cat back exhaust, cai, centre force clutch and run premium fuel if any of that would make a difference?

 

Check your fuel pressure.

Maybe try some fuel injector cleaner. (seafoam?)

There is a TSB (technical service bulletin) on plug wire routing, but, as you have replaced the stock wires, I am not sure if that would even apply.......

Throttle body spacer is a waste of money our the dodge trucks. Does nothing.

If you put it back to the stock tune, does it still do it?

 

Dirty or broken Camshaft Sensor (located in the distributor) can cause this issue.

And yes, even though the "Y" pipe was installed over a year ago, a clogged cat could be an issue, which means that the cat is faulty or there's a problem with the emission system of your truck.

 

hmm well i changed the camshaft sensor yesterday and its still doing it, how would i go about checking the fuel pressure and if it is a fuel pressure issue would that mean changing the pump? abd i'll try changing the superchip tuning back to stock and see what happens

 

if it is fuel pressure would putting an inline fuel pump be enough to boost the pressure?