# 2004 Grand Am 3400 suddenly very poor mileage in city **URL:** \ **Category:** Maintenance/Repairs\ **Tags:** fuel-economy\ **Created:** [January 26, 2015, 8:05am UTC](https://community.cartalk.com/t/2004-grand-am-3400-suddenly-very-poor-mileage-in-city/88832 "2015-01-26T08:05:37Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![eisjeff](https://avatars.discourse-cdn.com/v4/letter/e/41988e/32.png) [@eisjeff](https://community.cartalk.com/u/eisjeff)\ **Post date:** [January 26, 2015, 8:05am UTC](https://community.cartalk.com/t/2004-grand-am-3400-suddenly-very-poor-mileage-in-city/88832/1 "2015-01-26T08:05:37Z")
My 2004 Pontiac Grand Am with a 3400 engine and 205,000 still gets 27 mpg on the highway but suddenly only getting 13 in the city. The city mileage was 23-24 until the last couple of months. Changed oil, replaced air filter, not surer what to do next. ---
**Author:** ![Tester](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/tester/32/15976_2.png) [@Tester](https://community.cartalk.com/u/Tester)\ **Post date:** [January 26, 2015, 8:09am UTC](https://community.cartalk.com/t/2004-grand-am-3400-suddenly-very-poor-mileage-in-city/88832/2 "2015-01-26T08:09:49Z")
No Check Engine Light? Tester ---
**Author:** ![db4690](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/db4690/32/2583_2.png) [@db4690](https://community.cartalk.com/u/db4690)\ **Post date:** [January 26, 2015, 8:32am UTC](https://community.cartalk.com/t/2004-grand-am-3400-suddenly-very-poor-mileage-in-city/88832/3 "2015-01-26T08:32:16Z")
@eisjeff‌ Is the engine reaching operating temperature in a timely manner? If not, might be time for a thermostat ---
**Author:** ![the\_same\_mountainbike](https://avatars.discourse-cdn.com/v4/letter/t/c89c15/32.png) [@the\_same\_mountainbike](https://community.cartalk.com/u/the_same_mountainbike)\ **Post date:** [January 26, 2015, 8:33am UTC](https://community.cartalk.com/t/2004-grand-am-3400-suddenly-very-poor-mileage-in-city/88832/4 "2015-01-26T08:33:20Z")
Also, when was the last tuneup? ---
**Author:** ![db4690](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/db4690/32/2583_2.png) [@db4690](https://community.cartalk.com/u/db4690)\ **Post date:** [January 26, 2015, 8:52am UTC](https://community.cartalk.com/t/2004-grand-am-3400-suddenly-very-poor-mileage-in-city/88832/5 "2015-01-26T08:52:57Z")
Does it still start easily? Is it running well? ---
**Author:** ![the\_same\_mountainbike](https://avatars.discourse-cdn.com/v4/letter/t/c89c15/32.png) [@the\_same\_mountainbike](https://community.cartalk.com/u/the_same_mountainbike)\ **Post date:** [January 26, 2015, 9:28am UTC](https://community.cartalk.com/t/2004-grand-am-3400-suddenly-very-poor-mileage-in-city/88832/6 "2015-01-26T09:28:26Z")
One additional question; have you had this car for a long time or is it new to you, and do you live in an area where the temperature has taken a dive these past few months? Okay, that’s two. But they ARE related! {😛 ---
**Author:** ![BustedKnuckles](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/bustedknuckles/32/25_2.png) [@BustedKnuckles](https://community.cartalk.com/u/BustedKnuckles)\ **Post date:** [January 26, 2015, 4:25pm UTC](https://community.cartalk.com/t/2004-grand-am-3400-suddenly-very-poor-mileage-in-city/88832/7 "2015-01-26T16:25:44Z")
Are you sure the transmission is shifting through ALL the gears? ---
**Author:** ![system](https://global.discourse-cdn.com/cartalk/original/3X/1/d/1d47c66a543aa6c5a7873bb2320858f978ff52ed.png) [@system](https://community.cartalk.com/u/system)\ **Post date:** [January 26, 2015, 7:19pm UTC](https://community.cartalk.com/t/2004-grand-am-3400-suddenly-very-poor-mileage-in-city/88832/8 "2015-01-26T19:19:58Z")
One of the things I can think of which would suddenly change fuel economy is a leaking fuel pressure regulator. Do you have any symptoms like hard starting after warmed up? Poor idle? To check regulator remove vacuum line going to it and check for the presence of fuel.