Rough Idle in gear 1994 Celica ST (automatic) Options

[Noahwhite2014]

So i have purchased a 1994 Toyota Celica ST Hatchback (Automatic) from a friend a week ago, but he's not available now since he moved to another country (which is why he sold it to me). Ive always been into Celica's but never owned one.

Now that i have it, I'm having an issue with a low idle while in anything except park or neutral. Also, this problem does not happen once i start the car. When i start the car, it will run fine and idle at about or a bit under 1K RPM whether in park, reverse, neutral, drive etc... But once i start driving and bring the RPM above 2k, when i stop and idle again, the RPM drop to around 400-600 (sometimes even lower) and the car shakes when its around this rpm and then smooths out when the RPM gets above 2k

Any idea what the issue with this could be?

I would really love to get this car running well again like when i drove it a year ago or so and it was awesome!

There is a short ram intake on the car. But i don't remember if it was on when i drove it a year ago, i don't know if the intake could cause this problem. It has no brand that i can see, so i can add pictures if you would like.

Thank you all so much in advance!!

[Special_Edy]

Unplug the efi fuse or disconnect the battery for 30-60 seconds. This will reset the ecu to factory settings so it can 'relearn' the engine.
Maybe clean out your idle air control valve on your throttlebody and check your ignition advance with a timing light if you can get your hands on one.

A 100-200rpm drop when the engine is put into gear is normal. Idle speed is usually measured in Drive on an auto, not in park. Thus the manual idles 200rpm higher since it is measured in neutral.

[Noahwhite2014]

My car does this too, in fact sometimes it's so bad I feel as if it's only starting on 3cyl, it actually sounds like a diesel when it does it...
This Video Of The Problem shows when it is terrible. The car will be shaking violently inside and sounds like it's gonna explode...

Also with your AC problem, I had that EXACT same problem, there is a valve and I cannot remember it's name but I did post somewhere before about it. I cleaned it and it solved the AC problem.

My car only sounds like yours when the AC is on, hopefully mine doesn't get that bad. But yeah my car is sounding like a bus just scaled down...

Unplug the efi fuse or disconnect the battery for 30-60 seconds. This will reset the ecu to factory settings so it can 'relearn' the engine.
Maybe clean out your idle air control valve on your throttlebody and check your ignition advance with a timing light if you can get your hands on one.

A 100-200rpm drop when the engine is put into gear is normal. Idle speed is usually measured in Drive on an auto, not in park. Thus the manual idles 200rpm higher since it is measured in neutral.

I'll disconnect my battery today before going out to brunch since ill be catching a ride, hopefully it helps with the relearning process. Ill try to clean out my IAC again since the first time i didn't do a good job i believe. Im not sure how to check the ignition advance with a timing light, but I'm fairly sure my dad has a timing light since I've heard him talk about it before. I will let you know