Car won't accelerate with AC on?

hyundai
rpm
tiburon

#1

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.


#2

Did your check engine light come on?


#3

No, but it never has and neither does my gas light, so it might not work.


#4

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.


#5

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.


#6

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?