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If you can get a positive fix from another shop, it time to go back to the original shop and demand a big refund.

To spend $1000 with no results is ridiculous.

Has a compression (wet and dry) test been done with the engine cold? Can you track the miss down to 1 cylinder or is it random?

I agree that you "certified" mechanic leaves a lot to be desired. He should have done the above tests before replacing all the injectors. Also, the injectors should have been tested before replacement. That's the trouble with many mechanics, they just replace parts until the problem is solved and you end up with paying to replace good parts.

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