My 96 blazer wont idle when first started. Have to hold down gas pedel untill it warms up a little

David do you notice any coolant drips on the ground?

check battery and connection,fuel filter,air filter,spark plugs,it is cold put some gas anti freeze in tank.

double chek vacuum lines first..or O2 sensor if you have one...

Have the IAC (idle air control) valve checked or replaced. This unit controls airflow throught the intake-engine when the gas pedal isn't pressed!!

1. does engine run rough at idle?
2. if so vaccum leak or tuneup problem
3. if not idle speed control motor may be sticking when hot
4. when wont start will it fireup if you barley push down on gas pedel while cranking engine
5. if so replace or clean idle air control motor (located on throttlebody

Check & replace ambient air temperature sensor

i would clean the injecters

sounds real easy either a bad idle air control solenoid or more likley a blown throttle body gasket. to test fro a blown gasket, with engine running and cool spray carb cleaner or brake cleaner around base of tb were it bolts to intake. when it hits the bad area, should idle down and be normal for a second or 2. iac is possible,try this first since its so common and let me know

Could be several things but here are the known culprits:

1. Clogged or worn Fuel Filter
2. Clogged fuel line or injector(s) or throttle body.
3. Worn or dying fuel pump.
4. IAC valve may be bad and needs to be replaced.

you may have a bad engine coolant temp sensor. that is what frequently causes that issue on dodges