Changed spark plugs, now runs rough - thoughts?

Hey guys,

Yesterday I changed the spark plugs out on my 2012 V6, fairly simple job. I have changed many spark plugs in the past on other vehicles and never had any issues. For some reason, now my truck has a slight shutter while driving, almost like a short miss-fire but no lights come on. Almost feels like its about to stall out for a split second, its sporadic and I only really notice it under load.

Before I go taking everything apart again, does anyone here have any suggestions to what it might be? I have tried searching through the forums but its too specific of an issue to find for my self. I did change them to iridium spark plugs, but should that really cause this? I also changed the battery at the same time, but again, that shouldn't cause any issues...

Thanks in advance for any help you might have!

 

Did you gap the plugs? Or were they pre-gapped?

 

Happened to me as well on my 2012, one of the plugs had a hairline crack. I waited until it threw a code to figure out which one -- it takes a bit longer than you might think, but it caught the right one.

 

Bad gap one or more plugs? Plug not fully torqued? Coil pack not fully seated? Contacts dirty?

 

Bad plug....isolate then replace with new plug.

 

I went to buy Iridium plugs at the Toyota dealer.The parts guy,a tech and the service advisor all told not to use them.The truck won't run right.

 

They were supposed to be pre-gapped which is why I got them. Could not find a gapping tool anywhere except an old crappy wire one I already had, which I'm not sure I should trust. I think I might drive it a few more times, see if I can get it to throw a code before taking it all apart.

Thanks for the suggestions, did not expect such quick input!

 

If you are within the emissions warranty period, you have to change every 30K miles with standard copper plugs. Others will work, they will just void your warranty. It should run fine, but fresh copper plugs every 30k is cheap and easy.

 

on my 3.4l v6 it was copper core plugs DENSO dual electrode every 30k miles but usually the plugs were in such good shape except the gap, id just regap and use them till 45k or more miles

 

Both of these were my first thoughts.

 

First thing I would do is double check that no vacuum hoses were left or knocked loose. Second dbl check all coil pack connections.

 

My bet is cracked porcelain on a plug

 

Wait till there’s a code and go after that plug.

 

hopefully DENSO or NGK Plugs were used

 

Easy enough to pull, check gap, check plug, and reinstall. That way you can check if you put everything back right.

 

Pre-gapped plugs are easier to install and you can get them in other options than iridium. Most pre-gapped plugs are set at .042 and have to be adjusted for some make and models. Reset the gap or change to stock plugs and problem will be fixed.

 

No, this is wrong. It will not void the warranty.

Iridium Plugs always come pre-gapped and they should not be adjusted as the iridium is very hard and very brittle. Check the gap and if it is wrong you take it back for a replacement.

But I would go back to stock recommended Copper Plugs.

 

For gapping them, just use a set of feeler gauges. I think I got mine from napa for 10$ or so. Gap to .040 to .041.

 

com’on man.... Seriously? Stop posting incorrect fear mongering statements that are false. Sheesh.