I have a 1992 Cavalier 2.2L and am wondering if it would be at all possible to upgrade or change the ecm to accept an upgraded prom chip. This is a circle track dirt car and am looking for any kind of hp gains possible. Ive already done the IAT resistor mod and put in an inline piggyback mod on the coolant temperature sensor. any help would be appreciated thanks!

You won't get any gain out of either of those mods in a 1992 car.

There is nothing aftermarket available. You can use a EEPROM with a different tune if you want, but there really isn't any reason. The engine needs mechanical upgrades to see any gain from a reflash.
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