2004 Jetta 1.8T Ignition Issue
 

Hello everyone -

Last weekend, I changed the plugs in my jetta with NGK replacements - iridium core.

They came gapped at about 0.95mm, and the service manual specs 0.8mm max. I put them in without thinking (i.e.,I walkedaway for a while, came back later and put them in without setting the gap)and test drove the car and it ran fine.

This morning, my wife was driving it to work, she laid into it and it started to lurch, and a flashing warning light came on (she couldn't describe it, but she read the owner's manual entry to me, and it said something to the effect that you should drive it without hard acceleration until you take it to a garage - it mentioned that the light is likely emissions related).

It's continuing to run rough, even at idle, she limped it to work (about 5 miles) and will limp it home.

Of course, the first thing I do when I get home will be to set the gap to the plugs at about 0.7 or 0.75mm.

Will that fix the issue, or has the car's computer taken over in an attempt to fix the issue and permanently screwed it up without taking it to the dealership to get reprogrammed?

Also, why would this not have been an issue when I drove it around the block after I changed the plugs? But the first time she lays into it, it misses, and then it goes haywire?

Any ideas?

Thanks -

RE: 2004 Jetta 1.8T Ignition Issue
 

Well, I've heard that the iridium cores produce an ion field and interferes with the computer. I ALWAYS buy plugs from the dealership, you can never go wrong there. Anyways, besides what I've heard, just run the codes and see what they say.