Morph,
If you had an intermittent problem, I could many hours of diagnosis, but you have a chronic problem that should have been diagnosed in 3 hours or less. MB has routine lists to follow in proper order to lead you to the problem component. Sounds like this shop is easter egging. Ask if they have a fuel pressure gauge with all the fittings to tie into your fuel distributer to measure fuel pressure with the engine running. Ask if they have a chart that shows the resistance reading of the temp sensor at different engine temps. Maybe you need to find a shop that is better equipped.

Peter

__________________
Auto Zentral Ltd.