Changed Plugs Truck running Rough - Help!
 

Hi Folks,

Hopefully someone can help. We have a 2003 Trailblazer, 6 cyl. Yesterday I was changing the spark plugs and I noticed fresh oil around the top of some of the plugs. When I took the plugs out I am sure some of the oil got into the cylinders. Now the truck is running extremely rough, changed the plugs and still running rough. Three questions, it looks like there is a gasket possibly leaking any ideas? Did I hurt anything and what should I do?
Thank you very much, this is my wifes work car and I need to get it fixed ASAP

To stop the oil you need valve cover gaskets. What kind if plugs did you use? What gap did you set them at?

Thank you for the quick response. AC Delco 41-103's. They are Iridium plugs and I was told I didn't need to gap them. I tried those and put the old ones back in and it still ran bad, maybe fouled? I was reading on the valve cover gaskets, do you think I could do them without emptying the freon?

Thanks Again!!

If I had a bad Ignition coil shouldn't I be getting the check engine light?

yes you would get a code for misfire on ## cylinder

silly question but could you have mixed up wires - only asked cuz that would be something up my alley!!

no can do
 

cant mix up wires they are too short and there are no plug wires

I would suggest you go back thru the plug connections for the coils , a lot of times and have seen this discussed many times you don't get those coils snapped back on correctly and it causes problems . You have the correct plugs and no do not gap those plugs ! It is more likely something like this if the vehicle did not exhibit this behavior before the plug change, a little oil in the plug well would not likely cause an issue as long as it isn't a big pool .

Working on the neighbors 05 Inline 6 4.2l. Did the same thing, all I did is change the plugs, and it runs bad, if even at all. Sputters, won't even idle on it's own. Can't cross the coil on different coils as they all have a set amount of wire going from the harness to each coil and to get it wrong you would have to criss cross the wires to the coil packs.

How was it running prior to the plug change?
Did you verify the gap of each plug?
Double check that the plugs are the correct ones, preferably OEM and not aftermarket..
Are the wires firmly seated, did you feel and hear the "click"
Its possible the wires are bad and got even worse when handled when removing for the install.
Did you use any anti-seize compound, doing so can disrupt the proper grounding of the plug to the cylinder head...