2000 Chev Prizm

I have a 2000 Chevrolet Prizm that runs great when it’s cold outside. When the outside temp gets above 50F, the car will start, but will run poorly, and has virtually no power until the car has “warmed” up a bit. Any suggestions would be greatly appreciated. PS it has about 85,000 miles on it.

Temp sensor?

Have you checked for stored codes?
Has it been maintained per the owner’s manual?

Temp sensor?

Have you checked for stored codes?
Has it been maintained per the owner’s manual?

  1. Have not checked for stored codes… How can I do that?
  2. Oil changes, yes. I’ll have to check when the air filter was last changed. Spark plugs haven’t been changed since I’ve owned it (Aprox. 36K miles)

Take it to a mechanic and ask them to scan the ECM for any trouble codes. If you are willing to DIY, go to a local auto parts store and borrow one. You give them a credit card for a few minutes as security and they loan you the code reader to scan the ECM. If you don’t know where the connector for the scanner is, ask the folks at the parts store. They will give you instructions on how to operate the scanner. After you collect the codes walk back into the store and they will print the trouble codes out for you. Post them here.

The Prizm/Corollas I owned called for 30K spark plug change out. At 85K you could easily invest in air filter, spark plugs, new plug wires and dist cap before trying any other diagnosis.

Places like Autozone will download the codes for free.

If the spark plugs are original, change them. And if you have a distributor ignition system (I don’t know if Toyota was using coil-on-plug systems yet in 2000) then change the distributor cap, rotor, and wires.

While a car overdue for these parts will generally run poor when cold, a cold system bypasses the oxygen sensor input loop to allow the engine to run rich and that could compensate for tired plugs or ignition components. That could allow the engine to run good cold and hot, but not in between. Besides, it’s always good to be sure the basics are in good shape first when troubleshooting this type of problem.