Just got done with plug( ACDelco)and wires. Idol was great then after about a day it started to idol rough. Through a code 0302 # 2 cylinder misfire pulled the wire re-seated them to D C and plug cleared code. Ran great for a day then through a 0302 code again. Repeated the same process I noticed the wire that went into the DC had no resitance so I made sure it snapped in. Still has a rough idole and it is hard to start after it warms up. Could the DC or the rotor be the cause? Plan to do a fuel pressure test sunday but not sure if it is the cause of the problem. Any suggestions?

 

Just some things to check. Make sure the spark plug is in tight and has the correct gap. I'm assuming when you say ACDelco plugs that you got double platinum? And also make sure no wires are arcing. These two are easy to overlook. If it's something else by coincidence check your egr valve and throttle body for carbon build up. But it most likely has something to do with the spark issue. I'm going to say spark plug gap or arcing wires. Let me know and I can think of other things.

Edit: It could possibly be the distributor cap and/or rotor. Most people change the distributor cap and rotor out with the spark plugs because of how inexpensive the distributor cap and rotor are. If the spark plug gap is fine and the wires aren't arcing, I'd definitely look into this next.

 

You could have a bad wire as well. Try to move the wire to a different plug and see if the misfire follows.

 

Thanks guys,
Gonna change out the DC and Rotor this weekend. The guy at the parts house told me do not change the gap on the acdelco for fear of the tip breaking, however I was not impressed with his ability to answer some of my questions. ACDelco DC would be the way to go Correct? Found info that the towers are copper and less chance of spark jumping. Your thoughts?
Gap should be 60 right?