I have a 1995 maza 626 with a 2.5 when it is cold it runs great once it warms up runs like crap. help?

When the engine is cold,the computer ignored all sensors (open loop),run the engine at default values,usually more gas (rich mixture)since oxygen sensors only work when they get hot (hence heated oxygen sensors).So you should check your car's sensors,like mass air flow and oxygen sensors,after the ECM senses operating temperature,it depends on those to put gasoline through the fuel injectors.Hope this helps.

when is cold the engine intake is cold too so the air passing by is the ideal for the car once the car make more heat the mixture of the gas and air become lean and it lead to failure

the ecu works with that too when all sensors are cold it send more fuel so it can heat up more faster, when engine reach the correct temp that feature turn off and thats why you feel the car slow when in heats up

if you disable that feature you will spend more gas on daily driving... but it can be fixed... for for a shop and get a compression test, maybe your engine is going down too much

do a GOOD tune-up it can help

Have the thermostat checked out. It might be the opposite of what you think

check your ratiator hoses or the ratiator might have a hole