Mirage tranny going out?

[Gandalf]

So, my ex-girlfriend's 1999 Mitsubishi Mirage (1.5L automatic) has been acting up a bit lately...occasionally when the engine is fairly cold (withing the first few minutes of driving) if she stops and then starts (like a stop sign) the engine seems to lose power and accelerate very jerkily, until it gets up to a certain speed and the its fine.

I haven't felt it personally, this is just what she told me...I couldn't really get any real details from her. And she says it usually happens in the rain, which I think might be just coincidence. I gave her a list of things to look/listen for next time it happens, but my initial diagnosis is the first gear wearing out...which of course means rebuilding the tranny. Am I correct, or could there be some other issue at work here?

[legoman786]

I would check the fluids, and drive it for yourself.

Check the filter as well... also the shift solenoid. I can't recall which part it was, it tells the trans when it needs to shift, but it gets blocked with bad/old fluid. If you pressure wash it out, it will be as good as new and save you anywhere from $200-$500.

[lautinjr]

sounds like she has a generic old misfire possibly from a clogged Cat sinces it's temp related. I would take a look at the O2 sensors to see if rear is getting exhaust flow, or just wat till it acts up then pull the front to free up the exhaust. Is the poblem still there with the front removed?

[Gandalf]

Well, it's pretty intermittent - she says it happens once or twice a week - so I'll wait until it gets more common then try out what you guys suggested. Thanks!

[Mr Car Guy]

Definitely sounds like engine, not transmission.

Does it ONLY happen during warm up?

Lots of power when warm?

I'd be inclined to think the "CTS" is (Coolant Temp Sensor) is out of range. If the sensor doesn't send a valid "cold" signal to the ECM, it will run lean and stumble during warm up.

[Gandalf]

Well, she says it starts and runs fine, but occasionally within the first few minutes of driving, if she stops at a stop sign/light, then starts again, the power cuts in and out up until it a reaches a certain speed, then its fine. She says the engine doesn't sound any different, though, it just feels different.

She's about as car-savy as Moses, though, and she hasn't been able to do it when I'm around, so I can't say for sure that it's not running rough, but she think sounds normal. However, she also said it doesn't seem like the RPMs are spiking, so I dunno.