weird problem during traffic jam yesterday
 

So i was just stuck in traffic and for around 20ish minutes the car kept jerking back n fourth at 1st gear im in an AT frs. It would drop from 1k rev down to 500 and then back up while rolling.. Then the A/C started warming up and then it turned completely warm air for a good 5 mins... even while stopped it randomly went from 1k rev down to 5 etc etc.. not sure what happened is it just my car or is it normal?

I believe i have posted in the wrong topic how can i move this to the issues category?

Check the AT fluid level???

I'll bet that you began to overheat and the system shut off your AC compressor.

You arent really supposed to use the AC unless you are moving.

oh shoot really? =[ my 86 what have i done to u!!!!! i really didnt know :bonk:

For seriously? That's about the dumbest thing I've ever heard, but I could genuinely see Subaru saying it with a straight face.

On the manual if you bog the engine it will definitely jerk back and forth, which is typical of subaru engines. The AT version should keep itself from bogging in this way.

eh, are you sure you weren't barely hitting the pedal? at really slow speeds mine will "jerk".


as for the "ac not meant to be used unless moving"...ill...just leave that alone.

The jerking is the torque converter locking up. If you shift into 2nd before coming to a complete stop, it won't jerk.

The AC thing is "normal" in these cars. It's the AC compressor cycling.

I have these issues too ...but if you do a search it's somewhat normal.

I'd have to agree with the AC theory. Last week it was 90+ and I got to work a bit early so I was sitting in my car waiting to start. I had my AC on and my idle was very erratic. I turned off the AC and the idle went back to normal. I turned the AC back on again to see if the idle would go nuts and low and behold it did it again. I got out of my car and popped the hood to take a look. A few seconds after I popped the hood the the high fans turned off and idle went back to normal (with the AC on). I guess it just gets really hot under their. As soon as I shut the hood, the high fans turned on again and the idle went erratic. Heat and the high fans definitely seem to be a contributing factor.

I also have an auto and if I'm in first and the car gets up to 9 mph or a little higher and I let off the gas, the car will start jerking until it goes to second. I never noticed anything with the ac though.

I'll try to explain slowly....
Air Conditioners are heat pumps. They pump heat out of your interior into (wait for it) into your radiator (the thing trying to cool your engine).

AC systems take quite a bit of power: both HP from the engine and extra electricity for the fans (more drag on the alternator).

So while sitting in bumper to bumper traffic you are running a car in a way that generates the most heat while providing it the minimum cooling capability.

The system can detect the rising temps in the cooling system, first the car will turn on the electric fans to try to provide extra cooling for the radiator.
It even has more than one speed for those fans.

If that is not enough, it will take further measures and turn off your AC compressor. Why? because it knows that it generates more heat.
So I will rephrase "People who know what is good for their cars will not sit in traffic, not moving, with their air conditioner running"

This week I took 2 cat naps in my car with outside temps in high 80's to low 90's. My car sat for about 30 minutes this way each time at work. If you leave the AC on 1 (for FRS), the idle will be erratic with fans cutting on and off. Leave the AC on 2 and it will be smooth and consistent with fans always on. No rough idle issues. When it was time to get up and pull into the main parking lot the car drove fine. I am in an manual however. Cannot say much for auto.

I know how it works, I just think it's stupid for the manufacturers to decide it's ok to turn off the AC if the car isn't moving. I'd rather have paid a few more dollars for a larger radiator than be stuck in a traffic jam on a hot day and have my AC shut itself off.

its really interesting good thing it's not something wrong with my car.. i was pretty scared for a while @-@