Loss of Power- Stalls & Stops

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Has a "Loss of Power", stalls & dies,but runs better in neutral @ stop lite. Passed auto emmissions ntest.Owned for 10 yrs/$152K miles. Maintained religiously.Out of a job so can't replace auto @ this time. My mechanic drove it, & told me he thought might be a "piston". Does not do heavy engine work. Told me to check it out w/rep mechanic shop in area. They all have asked for a min of (3-4) hrs-(labor only). Unable to get a verbal bid for a piston from anyone. Any help is greatly appreciated. Thank you in advance for your time.