Have a 6.9 1984 F250 diesel, I have not been able to find a mechanic in Ca to fix it right, been to three shops and Iam repair poor over 12 k and my truck is in worse shape runs like crap, anyone know of a good diesel shop in ca
What you're really running into, is that the number of people with deep experience with IDIs - is just getting thin. That said - expand your view of who can work on it.
Sacramento is a Farm Town, surrounded by some of the worlds most productive farm lands. Therefore - you will find people who work on the many diesel's which you see in farm equipment, and people tend to try to keep them running - including these IDI motors. I'd also look for shops which work on RVs and light trucks (3/4, 1 Ton etc are Light Duty trucks). Lineville Brothers (El Camino and Business 80) does most of my non-engine work.
Imler Diesel has been in town for decades. They used to do performance diesel work, but they're not doing as much work as they used to, and have been selective about what they work on. Start there - if they don't want the work ask for a referral given the issues you're having.
Orangevale Diesel is also known to work on a lot of Light Duty Diesel trucks - but I'd think of them as more of a "spec shop" than an engine builder. Transmissions - A1 Transmission on Fulton Ave, is known for doing Imler's performance and transmission rebuilds.
Use Google Maps, and start calling around town. Do a bit of research to understand what other agriculture tractors and heavy equipment they were used in - and start calling to find out who is still working on old mechanical diesels. You want to know if they a) work on mechanical diesels, specifically IDIs, b) have a mechanic who specializes in them, do they regularly do engine work? Etc.
If you really can't find something, then I would call Daves in Utah. They might have some ideas, and even take the work - When one of my Ford's engines go - I've already decided to trailer mine out there. They do good work, and more importantly - they're honest.
https://shop.davesautorepairutah.com/
The last idea - is to convince one of the really smart wrench's here on the list. I'm not a good wrench, but more to the point: if I start another project I'm likely to be sleeping on the couch for the foreseeable future.