Vacuum leaks.

 

Either at the intake gasket, or at hoses that get brittle.

 

Have ALL the vac lines changed. You live in North Dakota. What do you want from 15 year old rubber in Sub-zero weather?

Vacuum leaks.

 

Either at the intake gasket, or at hoses that get brittle.

 

Have ALL the vac lines changed. You live in North Dakota. What do you want from 15 year old rubber in Sub-zero weather?

+1. Spray the exterior of the elephant trunk (big rubber/plastic) hose from air cleaner to intake manifold with carb cleaner while engine is running. If revs increase or decrease, you've got a vacuum leak. No leak? Spray on smaller vacuum lines and vacuum connections. You might be fouled with carbon in the intake manifold too. I'd introduce about a half can of Seafoam into the intake manifold via the PCV valve or brake booster line to clear some carbon out.

It was installed by a mechanic

[...]I am on the road...........

How do you reset the ECU?

I sympathize -- your situation must be frustrating. If you aren't able to directly interact with the mechanic, then it's unfortunately possible that parts are being replaced without diagnosis. In your other thread concerning this problem, I asked if the fuel pressure regulator operation had been checked, but I didn't see a reply. It would have been useful to know both the fuel pressure and whether applied vacuum was properly controlling it. If the pressure was correct, it would obviously suggest looking elsewhere; if it was wrong, the vacuum (and associated hoses, etc.) would typically be checked before replacing the regulator.

 

Probably the easiest way to reset the ECU is to disconnect a battery cable for a while -- 30 minutes will ensure the stored data will be erased and that the memory won't be corrupted (which sometimes happens with a shorter time). Of course, radio station presets and clock settings can be lost. When the cable is put back and the engine started, let the engine warm for about 10 minutes without touching the accelerator so that the ECU will 'relearn' proper idle conditions.

 

Checking for intake vacuum leaks has been suggested. Such leaks could result in either a lean or rich mixture, and be the cause of starting and other problems. For example, any air that enters the intake beyond the airflow measuring device (either MAF or MAP) is an amount over what the ECU 'thinks' the engine is using, and insufficient fuel will be injected for the air volume, resulting in lean running. On the other hand, if a leak causes loss of vacuum to the fuel pressure regulator, the pressure can be too high.

 

Considering the circumstances, it might be prudent to have the problem diagnosed by a dealer or independent shop very familiar with Subarus if you're unable to look things over yourself.

I want to expand on why it might be time for a dealer or sharp independent to look things over. Assuming that the problem's cause isn't obvious (since it hasn't been resolved easily via 'remote control'), good diagnostic skills could be key. For example, what if the timing belt has slipped a notch or two? It might explain starting and gas mileage issues, yet without some basic tests to rule that out, parts could keep being thrown at the problem. Sometimes it's worthwhile to bite the bullet, even given the chance that something 'simple' was missed and the result is 'overpaying'.

I second that comment ob99w. Sometimes it is worth the money to get a proper diagnosis and not just throw parts at it. If you are unable to do the test properly, you should take it to someone who can.

Yes I agree and it's going to the Subaru dealer. I would

hope the heck the mechanic checked the pressures before

installing a new fuel pressure regulator........ but I will find

that out later.

Yes I agree and it's going to the Subaru dealer. [...]

Best of luck. Please let us know the eventual outcome.

Sundance,

 

I have the same thing going on. What was your fix back in March?

Bump,

 

Sundance, you out there.