Q: No compression cylinder 1, car shakes/vibrates and runs rough, decreased gas mileage.

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Cylinder 1 misfiring. Car idles and runs rough, car shakes at low and high speeds, badly decreased gas mileage. Mechanic did a compression test on all cylinders. Cylinder 1 no compression, 2-4 ~100psi each. Possible Valle issue? Rebuild or replace with used engine? Not worried about resale value.

My car has 168000 miles.
My car has an automatic transmission.

Yes, absolutely, rebuild or replace the engine. The vehicle itself is a recent model year so your least cost option will be to repair what you have. And, you’re right, "re-sale value" is irrelevant in the calculation (good for you!). That is, the "cost to compare" in a situation like yours is what it will cost to get your vehicle running versus the cost of buying ANOTHER car. Least cost option, even with engine swap, is usually to simply repair what you already own. Zero compression in one cylinder could be as simple as a stuck valve, however, the low values in the other cylinders mean the rings are likely worn beyond good service, too. You can completely rebuild what you have (always a good option), buy a used engine (risky and requires lots of due diligence and precautions, but still possible), or buy a crate engine (most costly option). As you wend your way through this, we are here to help you. Some select mechanics in certain YourMechanic service areas will do engine swaps. Please simply inquire as to that option and we will help you as best as we can.

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