# Car won't accelerate with AC on? **URL:** \ **Category:** Maintenance/Repairs\ **Tags:** hyundai, rpm, tiburon\ **Created:** [July 26, 2011, 9:44pm UTC](https://community.cartalk.com/t/car-wont-accelerate-with-ac-on/66609 "2011-07-26T21:44:05Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![deannasue86](https://avatars.discourse-cdn.com/v4/letter/d/da6949/32.png) [@deannasue86](https://community.cartalk.com/u/deannasue86)\ **Post date:** [July 26, 2011, 9:44pm UTC](https://community.cartalk.com/t/car-wont-accelerate-with-ac-on/66609/1 "2011-07-26T21:44:05Z")
I drive a manual 2001 Hyundai Tiburon. I tried to take it on the expressway today and it took a long time for the RPMs to get high enough that I could shift gears. It seems to want to hover at about 2000. When I finally got into 5th gear, it would only go about 50-55mph with the pedal to the floor. When I turned off the AC, though, it would go about 70mph, but it lost speed quickly on hills and took a long time to regain it. I am not sure, but it seems like the gas mileage was substantially worse than it normally is. I didn’t notice any new noises or smells or shakes or anything like that. The car is just really lagging and my mechanic is closed for the night. I would like to at least have a guess what it is so I don’t have to worry about it all night. Thanks. ---
**Author:** ![keith](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/keith/32/5518_2.png) [@keith](https://community.cartalk.com/u/keith)\ **Post date:** [July 26, 2011, 11:26pm UTC](https://community.cartalk.com/t/car-wont-accelerate-with-ac-on/66609/2 "2011-07-26T23:26:52Z")
Did your check engine light come on? ---
**Author:** ![deannasue86](https://avatars.discourse-cdn.com/v4/letter/d/da6949/32.png) [@deannasue86](https://community.cartalk.com/u/deannasue86)\ **Post date:** [August 2, 2011, 2:26pm UTC](https://community.cartalk.com/t/car-wont-accelerate-with-ac-on/66609/3 "2011-08-02T14:26:05Z")
No, but it never has and neither does my gas light, so it might not work. ---
**Author:** ![missileman](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/missileman/32/1366_2.png) [@missileman](https://community.cartalk.com/u/missileman)\ **Post date:** [August 2, 2011, 2:31pm UTC](https://community.cartalk.com/t/car-wont-accelerate-with-ac-on/66609/4 "2011-08-02T14:31:13Z")
Two things come to mind. A tank of bad gas or a partially plugged catalytic converter. I’ve had both of these with 2 different vehicles and your description fits those problems to a “t”. It may be something entirely different though but they are worth checking out. ---
**Author:** ![cigroller](https://avatars.discourse-cdn.com/v4/letter/c/c68b51/32.png) [@cigroller](https://community.cartalk.com/u/cigroller)\ **Post date:** [August 2, 2011, 2:32pm UTC](https://community.cartalk.com/t/car-wont-accelerate-with-ac-on/66609/5 "2011-08-02T14:32:31Z")
How many miles are on the car? Describe your general approach to basic maintenance and then all the specifics you can. E.g. How old are your spark plugs & wires? Fuel filter? Air filter? The thing about the AC is that it puts a pretty heavy load on the engine since the engine has to run the compressor. If the car isn’t running quite right - for any large number of reasons - then the AC load will knock it down quite a bit. ---
**Author:** ![Caddyman](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/caddyman/32/23_2.png) [@Caddyman](https://community.cartalk.com/u/Caddyman)\ **Post date:** [August 2, 2011, 2:33pm UTC](https://community.cartalk.com/t/car-wont-accelerate-with-ac-on/66609/6 "2011-08-02T14:33:55Z")
The CEL (check engine light) should come on when you first turn the key on, then go out a few seconds after the engine starts…Is this a 4 or 6 cylinder? Mileage?