Stumbling Subaru

Maintenance/Repairs
1

I have an '06 Forester XT 2.5 turbo that has, what I can only discribe as a stumble around 2500 rpm. The car’s maintenance is always up-to-date, and never has anything under 91 octane run in it.This started out when you had the cruise set and now does it all the time whether or not the cruise is used. I’ve had it to 2 shops including a Subaru dealer that had it for a month and couldn’t find the issue. We’ve been through injectors, coils, maf sensor, etc. to no avail. The trouble code that we’re given is a misfire in cylinder 1. We discovered, while trying to find the issue, that there was only 30psi in that #1 cylinder and the valve guides were the issue. So the motor was pulled, heads planed, etc. and new guides installed. Also, put in a new timing belt, and so on, that is usually done when the motor is out.They have done a leak down test and compression tests as well. This is my wife’s car and she absolutely love it, so I need to get this figured out. Any suggestions?

Doubletap

2

Are you sure that any valve guide diagnosis and/or replacement is not a misinterpretation or something?

Valve guide problems are practically unheard of and the low compression you cited was probably due to tight valve lash. Valve lash is something that should be inspected about every 30k miles.

Does your copy of the repair order showing a complete valve job (including possible replacement of any valves) as being done?

Did these guys toss all of those parts at the car before coming to the 30 PSI compression issue?

What are the current compression readings? (I would hope that this would be written down, but…)

3

There may be a problem with the throttle position sensor. The fuel pump might be another suspect also.