i have been trying to figure out what is causing this misfire code. less than year ago i did plugs, wires, rotor, cap. three months ago i had a misfire cylinder 6 code and it was a bad fuel injector, so that was the first thing i changed on cylinder 4 but the code came back, the wires to the fuel injectors are fine. i did a compression test and all cylinders are between 90-80psi. fuel pressure is 50psi. i also recently replaced the intake manifold gasket. im not sure where to go from here, any help is appreciated thanks

 

anyone??

 

Your post is difficult to understand. Did the misfire code come back on the same injector you replaced, or another cylinder?

There could be debris in the fuel rail.

Your new SP wires could already be failing. Make sure they are not touching each other or anything grounded. Look for shiny spots where they might be rubbing on the valve or engine cover.

Distributor caps with aluminum contacts have no longevity. Pay the extra for Brass contacts.

Your compression readings are pretty low, which might just be the gauge you used. At least they all read similar numbers.

Did you do the plenum pan gasket when you did the intake gasket?

 

New parts go bad all the time. A few years back I developed a misfire on #5 two months after changing my plugs to NGKs. It turned out the new plug was faulty. I changed and it's been fine ever since.

 

yes it is on the same cylinder, today i got a new cap and rotor (a good one). I canged plugs in that cylinder and swapped wires from another cylinder to see if the misfire would move and it did not. im not sure what the plenum pan gasket is, i replaced the gasket between the head and the intake manifold. as far as the compression readings, a few people said they are low and a few said theyare fine for an engine with 160k+, in the book it says min 100 psi. the plug are not oil coated they have a nice light tan color. im going to do a leak test, and replace the cap and rotor, ill post results, thanks for the input!

 

never mind on those compression numbers, cylinder #4 is at 120psi, i was starting the engine and letting it run for 2-3 seconds instead of pulling the coil wire off and letting it crank 4-5 times. much better the reading when done proper

 

new cap and rotor didnt work either

 

Is it running poorly? Does the CEL come back on instantly? Are you unplugging the battery to reset the ECM and clear the code?

I think the all knowing alloro has been having misfire codes for quite some time without ever finding a resolution.

If you have that much compression, I think that rules out internal engine issues.

The only thing I can think of is the #4 wire is being affected by the adjacent wires. There was a factory service bulletin specifying a certain routing to avoid this. I do not know which cylinders it was.

I like stripping the insulation off the old set of wires and doubling them up in any areas where the wires might touch, chafe, or touch a grounded item.

stev is pretty good at finding the bulletins.

I could not find it in a quick search, but look around here:
http://dodgeram.info/tsb/index.html

Just for grins, remove and file the battery to engine ground, inspect the battery cables closely for green or white corrosion, and if a engine to frame ground does not exist, add one.

 

And just what do I owe this unprovoked attack of sarcasm to?

 

Did not intend it as an insult or sarcasm. Want me to edit it?