Thread: Gas Mileage decreasing

Hey people. I am a little baffled. I was getting some good gas mileage 6 months ago. But since then its been decreasing. i have new plugs, wires, filter, PCV valve, and air filter. I did a throttle body clean and cleaned the sensors and ranSEA foam in the brake booster vacuum line and put some in the tank as well..
Car idles fine (900 rpm)and runs fine. There is a slight bit of hesitation when i stomp on it during acceleration. 2000 GP GT 145000km.

I am getting an o2 sensor (AC delco) soon. Hopefully this will work. Any other suggestions?

Platinum NGK, and I used alcohol to clean the sensors.

No codes. But I cleared some codes a while back,( low coolant ) as the heater bypass connector went, so I replaced it.

Well, my mileage has been down for a while. I just did all of this last week.

I get 400km (250miles) city. per tank

And when i pulled the other plugs out, i did notice 2 back ones were wet with gas. Fuel injector leak? The others looked great.

I used to get alot more. And i am super light on the pedal.

Would a unfinished drive cycle after removing neg. bat cable do anything?

Well maybe i will try the iridiums. cant hurt.

I've been having the exact same problem with my 2003 GP GTP..... I just replace my platinum plugs (which I put in a few years ago) with auto lite iridium....also replaced the wires.

I will post back any MPG improvement.

I hope it works for you Ron