the title pretty much says it all. ive been unplugging sensors and stuff trying to figure out why im getting bad fuel economy but they all look ok and when disconnected the car hesitates. but anyway when i turn off the car there is a release of suction sound from the throttle body. any ideas? it tends to do it more when the engine is warm. thanks alot!

most 3800'* with a modded intake system usually does that...at least just from my experience

if it makes you feel any better my truck does it sometimes too...and ive got the stock FWI on it

Mine does it too

ok, thanks alot. just trying to get to the root of my bad fuel economy. 1k miles set at 72 on cruise got me a real life avg of 25mpg. car said 32.

My Bonneville gets around 22-23 mpg (320-370 miles/tank) with typical leadfoot driving (about 85%-90% highway driving).

If I behave and drive like a typical grandma, the best I can get is 25 mpg (about 400-410 miles), and that was before my O2 sensor change.

Only other guess is an exhaust obstruction, and it is blowing backpressure out the intake. What kind of shape is the catalytic converter in?

my grand prix used to always do that, my friend used to always say the car is finally relaxing after you drove the **** out of it lol

not sure on the cat, or how id check it to be honest. it doesnt sound like its clogged or anything. if that were the case i think id have torque like my dads car from the backpressure lol.

Thread Title expanded and moved to it'* proper Mechanical Section. General Chat is for items that affect all platforms and "General Chat". It really helps the GearHeads, others with ownership of same/similar Models, the Forum regarding search bots, and our own internal search engine when we keep things in order. Thanx.

You know, now that I've thought about it, mine used to make the same sound before I fixed a vacuum leak. My guess is it'* the engine vacuum escaping.