I work at Honda/Acura dealer but I drive a 2003 Subaru Forrester automatic. I recently had the head gasket problem so I remove the heads had the valve job done and the heads decked. Everything seems perfect till it got warm and now has hard stumble at idle and take off....rechecked valve lash and timing marks the right side cam seeems half tooth off. Could they have taken too much off? Has anyone else ever heard of a machine shop messing up a Subaru head? Never had this problem on Honda’s but I love my Forester!! Any technical questions I’m ready for it just wanted to keep it simple and thanks !!!
Machine shops can make mistakes, and do mess up things. But it's more likely that you forgot to connect something, or have leaking old vacuum hoses/egr crap that was damaged while removing/putting back on during the work. https://www.subaruforester.org/vbulletin/f88/loss-power-idle-bob-surging-oh-my-89969/
i may have had a similar issue when i got my HG replaced a couple months ago. (and it's kinda funny as i'm still piecing together the whole story). anyway, they had to replace a head (edited to add; they said there was so much scarring from the prev shop's HG job that it needed a new one) and when they sent the heads off the guy didn't know they were different so that caused something to be off, which caused the lash to be off which lead to a burnt valve. they then had to send the head back to be redone, and a valve job as well...all i know is it took months and cost me a fortune! although, she runs like a champ now and i'm betting i get another 100,000 miles out of her good luck!
No CELs? Was the valve lash still within spec? Re: tbelt, did you count the teeth between sides? The double notches with the crank lined up tdc are often just slightly off (esp when looking at it from an angle with motor in). If they're lined up with the cover I wouldn't immediately suspect that to be the cause of your stumble issue.
