Hi, my legacy has been sitting for about 3 years and I just got it running a few weeks ago. The problem is the rpms do not stay between 1 and 2 when its a cold start. The engine will almost immediately dip down to 800 or so and start to misfire. It seemed like the idle valve wasn't working properly so I checked it and replaced it. Also noticed the warmer the car gets the lower the rpms tend to fall (around 500-300). It died on me at a stop light while the rpms were hanging around 200-100.

 

I've put new plugs/wires, coil, pcv, fuel filter, fuel cleaner, vacuum pressure checked, fuel pressure checked but I'm still at a loss on what this could be. Maybe a bad coolant temp sensor is causing the idle valve to open early?

Welcome to the USMB.

 

Not sure if you figured this out yet, but the coolant temp sensor might be the cause of an issue.

 

It sounds like you've done all the basic checks, including check for vacuum leaks. Have you checked for codes to see if any past codes are stored in the ECU? Instructions are on my site: http://www.surrealmirage.com/subaru/engine.html

 

BTW, good to have another Houston member with a first gen legacy.

thanks, no i haven't checked or replaced that yet. I don't have any codes tripping the engine light. Will that sensor trip the light if it goes bad? im gonna check vacuum again when i home tonight. yep i love them first gens too. im too broke to buy a newer one ><

Not unless it is real real bad.

 

Stale gas?

replaced coolant temp sensor no difference. still idles very low when engine is warmed up. compression checked first cylinder (gonna do the rest tomorrow) it was about 20 lbs. low.

Does your year have an EGR valve. If it does ,a sticking EGR valve will cause idle problems.

newp. no egr

replaced coolant temp sensor no difference. still idles very low when engine is warmed up. compression checked first cylinder (gonna do the rest tomorrow) it was about 20 lbs. low.

 

I should have read this post more carefully. Is it 20 psi. low. ( as in, its 20 psi. wow thats low)? Or is it, 20 psi below normal? Cars sitting for extended periods will usually have bad sealing valves (surface rust on valves and seats).

Usually running for few hours will take care of it. Are you sure you IAC is working?

its 20 lbs below normal. the gauge measured around 135 psi when the minimum is 156 psi. No codes on the computer. I let the car warm up and took the IAC valve to check the door; it was fully closed.

The door on the IAC valve should be about half way with it removed from the car and no current on it. You can kind of see that in this picture.

 

http://www.main.experiencetherave.com/subaru/images/iacvalvenew/DCP_6525.JPG