I switched to Bosch Iridium plugs 8 months ago. Made no difference. An after market air cleaner, such as a Steeda SRI, or any of the other cold air intakes available from FF sponsors may help. I have a Steeda, and gained 2 mpg. Just be careful when oiling the filter element, as the MAF sensor does NOT like oil.
Depending upon what your "city" driving is like, you may need a Vespa! Good luck.

 

Hey I changed to copper autolite 103s and I did see my gas mileage go up 1or 2 with a very smooth idle, and if you can't spend 200 or 300 for an intake search up stealth mod and it does help with the gas mileage but not so much on the horsepower.
-my experiance

 

Autolite 103s are good plugs and are also available as platinums so they will last a bit longer than regular coppers.

 

True, but there was a thread around hre really well writing up telling you the different plugs and the difference and the way it can help your car I'm at work I can't look for it right no but when I'm of I'll post the thread very well writing up and with facts not opinions

 

Autolite 103 plugs are the best we've found in these cars, but really any plug should give you better than 20 mpg without a serious engine or exhaust issue. How are you figuring your mileage?

 

Well I have tested about three times with half tank, I just divide Miles between gas gallons. Now I am making with full tank, maybe its more accurate.

 

flat tire!

I was checking my tires presure and my rear right tire has just less than 10 PSI I haven't notice this, the other ones were at perfectly 32 PSI. I have inflated and seems good now, I will post my mpg after doing this. I was getting 24 mpg before I am not sure if just a tire could drop 4 mpg

 

ok yeah the 10 psi tire is called almost flat which will drastically effect your mileage. Go with the 103's, cold air kit, bigger exhaust and test from a full tank.

 

NO, exhaust systems tend to decrease mileage. I lost 2 mpg when I went from the stock exhaust to a free-flowing exhaust. I had more zoom, but it cost me.

10 psi on one tire is going to cause you some problems. I don't know how expensive air is there. Here it's fairly cheap, and although it's not economic, I purchased a 12v tire inflator. If you decide to get one, the best company is Intermatic. These people were the first to market a 12v emergency tire inflator, and still make some of the best, longest lasting emergency tire pumps. I didn't go cheap, and bought their most expensive model without a rechargeable battery.

 

NO, exhaust systems tend to decrease mileage. I lost 2 mpg when I went from the stock exhaust to a free-flowing exhaust. I had more zoom, but it cost me.
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Interesting. I've always gained mpg with a cai and exhaust upgrade. I know there's a few folks on here that don't recommend under drive pulleys but I got 3 mpg out of just that when I put an abnormally small one on my old zx2. I averaged 31-34 mpg with mixed driving in my zx2 with cai, exhaust (2.25" catback with borla) and a custom racing crank pulley. I also have a 96 tbird with exhaust (3.5" single exhaust from mid cat back), mac cai and average around 20-22 mpg. This is with PI intake, cams and 4.10 gears as well. My 2002 GT averaged 24 mpg with mixed driving and maxed 28 going to L.A. from Sac. That had a steeda ram air, bbk off road x, stock cat back with flowmaster 4" tips.