HI,
My aunt has a 99 mystique 4cyl. She is having the following problem and I'm hoping for some help:
Her car will run fine at an idle, when you step on the gas in neutral it will reach 3-4k rpm and shut off (sound like a rev limiter). When you put the car in gear and try to move it has now power at all and will not move more then a couple feet. I put it back in neutral and step on the gas it will sound almost like it is flooded out then pick up slowly to the 3-4k rpm . There are no check engine lights on. So far her local "mechanic" has charged her over $500 to do trouble shooting. He has replaced both O2 sensors, map sensor, punched a hole in the catalytic converter, and replaced the muffler. He told her the car was not flowing enough exhaust (although it seemed to be flowing plenty to me). I am at a loss for what the problem might be with no error code. I checked the air filter and it is new. She is a single mother and it is her only mode of transportation with 3 kids, she can't afford to continue allowing him to trouble shoot on her $. I am capable of doing most repairs, but I need some suggestions as to where to look. I appreciate any help.
Thanks,
Dennis

have you tried fuel filter? i have mentioned before in another area of the site. my girlfriends car was acting weird. no power on hills, had to gradually increase speeds or it would hesitate and buck, made me almost think the transmission was going bad. in park it would rev up with no problem, yet in gear it would do nothing but cough, backfire occasionally, and have troubles with hills. i changed the fuel filter and it helped big time. about a month later it started acting up again. knowing that my cars werent having problems but hers was made me think. if the fuel filter opened up the pressure some maybe the strainer in the tank was bad. sure enough, i changed out the tank with an extra i had that had all good stuff in it. since the restrictions were gone since i changed fuel filter and the swapped gas tank had new strainer in it, the car has been acting like new again. havent had any issues since.

Hi,
Thanks for the suggestion the fuel filter was actually changed at the same time with no help.
Thanks,
Dennis

HI,
I got it towed to my house and after 5 min found the timing belt needed to be changed, but is this an interference engine?
Thanks,
Dennis

If it is your exhaust valves could be bent and not fully opening.

HI,
I fixed it with a new timing belt, there were several teeth missing which was causing the timing to be off slightly. It is just to bad he mechanic had already soaked her for over $500 before she brought it to me. It cast $32 for the belt and it runs great again.
Thanks for all the help!!
Dennis