i am working on a 94 subaru legacy and am a bit perplexed when i slow down fast, for example at a stop light or off of the freeway and the idle drops it doesn't remain constant, it bobbles when it gets below a thousand and sometimes it bobbles so much that the car dies, and a couple of times i haven't been able to get it started after that, i thought it was the idle air control valve but i replaced it and the problem continues, can anyone help?

Is it throwing any CEL's?

If the plugs are in good shape I would check the EGR valve and clean it.

If the plugs are in good shape I would check the EGR valve and clean it.

 

plugs are ok, egr too, and no bad cells, i was thinking ecm, but wouldn't that be malfunctioning all the time, not just at idle?

It isn't the ECM. You could try running some Seafoam through the intake and the other half in the fuel tank to see if that helps things.

Does the 94 even have an EGR? Thought it was fuel purge solenoid in the earlier cars?

No, the 94 does not have an EGR valve.

 

I'd spray some brake cleaner in the IAC valve tube. Also, run some seafoam through the engine.

Thanks for the heads up about the EGR valve fellas. I didn't know that.

Check all vacuum hoses as well. at 11 years old they are going to crack and leak vacuum!

Bust out the starting fluid and spray down all the vac hoses while the car is running.

If one of them is bad itll drop or raise in idle speed.

carb cleaner is a little safer than starting fluid and will be as effective. Just don't use brake cleaner it will make some toxic fumes. You may also check you MAF sensor. My Brother was having a similar problem with his '90 Legacy w/2.2L and that is what I found the problem to be. Just a thought.