I don't want this to become another MPG thread believe me. But here is my concern:
Back in July my A/C blew up (literally) so I to the dealer and it was a warranty repair, well while it was in there I had them clean the TB which had been sticking (I told them it was, not the other way around).

Well the guy had me do a 30K mile service because it was like $10 more than the TB service and was included in the 30K service. Well ever since I have gotten my car back my MPG has seemed much worse than it was before I took it in. I used to be able to drive 315 miles a tank (city), now I'm lucky to break 250 miles. I even tried resetting the ecu by disconnecting the battery and having it re-learn while I drove it nicely for a week.

So when I look at the paper work from the work done, it looks like the dealership used $1.98 plugs, would these cheap plugs possibly be my issue? If so what plugs does the 4G94 work best with? (I ask because my nissan didn't run well with certain plugs).... Any thoughts, opinions would be appreciated.

Oh the air filter was replaced as well, and I run mobile 1 full synthetic and it was recently changed. No SES

 

I just use the stock copper NGK plugs. I'd just make sure the gap is correct. That's probably your problem.

NGK BKR5E-11

Gap .039 - .043

 

I am confused we are talking about an 08 Lancer or the 04 OZ in your profile. cause the gap is different its around .029 i think

 

Your right it is for my OZ, I'm sorry can a mod please move my thread? I clicked the wrong engine tech link.

Thanks, I will check out the gaps!