Hello and welcome to Pearl/Just answer.com, Super mechanic here. I will do my best to help you with your question. If you need any more on it just let me know.
You will want to check the fuel pressure to see if it is too low. Also that the filter is not restricting the flow of fuel.
Then if the fuel pressure and flow are good, the exhaust may be a little bit restricted. You can have a back pressure test done on it at most exhaust shops to see if the cat is clogged.
If they are both ok, then you will want to take a sample of the fuel to be sure that it’s not contaminated.
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