Sunday I changed my spark plugs from stock AC Delco's to NGK TR55's. I gapped them to .060 (Like the manual said to) and installed them. Immediatly afterwords the car ran like complete crap, constant hesitation, popping, misfiring. Well today I pulled them out and the drivers side look normal (clean, slightly brownish), but the passenger side plugs were completely black!!! WTF!!! Any reasons anyone can think of why they would do this? One side normal and the other side black? I checked the coil packs and they were fine. I put back in my old spark plugs and problem was gone but now my idle is a little funny. Any ideas?

-Travis

 

Running the TR55's they should come pre gapped. I gapped mine to .055. I have even heard of .050. I know the stock ones are gapped at .060.

 

Take em down to .050 and see the difference

 

Yeah dude, I think you gapped them wrong. The gapping should be .055 or .050, the .060 was for platinum or iridium tips, can't remember, the NGK's are copper.

 

0.060" is factory spec, should be the same for any plug.

although running .050" should hurt anything.

are you sure you had the wires all the way on??

 

Not anymore. Factory spec on the replacement irridium plugs per some GM bulletin from ~2 years ago states the appropriate gap is now .040"...that is, if it should be the same for any plug. Some people don't think so though. So, I revert to having absolutely no clue. http://web.camaross.com/forums/showthread.php?t=375676

 

The gap issue is interesting, but why were the passenger side plugs fouled, and the other side nominal?

 

I will regap and install them this weekend, and I am still curious about the passenger side spark plugs are fouled? Any ideas?

 

the .040 gap only applies to the new plugs themselves. From the Bulliten: "Due to the different tip design, the gap of the spark plug has also changed." they are a different style of plug and regapping may cause damage. so the .060 gap should still be considered the manufacturers suggested gap unless using the new style plugs.

But I agree with Teke, Id say something eles was up. I have seen the platinum tips fall off (which causes a pretty big gap increase) and not have major running problems. the fact that it was all one side also leads me to belive that it wasnt the plugs. they shoudl have all given you a problem if you gapped them all the same. you said it was your pass side that was black, thats usualy the side that I remove the coil packs to get to. did you do that? If so its possible that you didnt get the harnes plugged back in securely. I actualy forgot to reconnect it at all once, after doing some mods, and the car actualy ran on 4 cyl, which surprised me, I didnt think it would run at all. It ran like crap, and I figured it out real quick, because it was obvious wiht the connector just laying there not connected.