My 2004 5.3 L runs fine when it’s cool and starts to stall when the temperature gauge is half ways could it be the feul pump or the crank position sensor?

SOURCE: I have a 2004 Chevy

Bad Stepper motors....the motors in your cluster are very weak... there is an upgraded motor x 25-168...cost 175.00 parts and labor to replace all of them. Ive repaired a lot of clusters with this very problem

Steve Allison

• 5569 Answers
• Posted on Jan 19, 2009

SOURCE: 2004 Bonneville - Temperature Gauge is Erratic

Since there is no voltage applied with the ignition off, if the gauge is not dropping down all the way, it is the gauge that has failed.
Temperature sensors are frequent failures but they are not active when the car isn't powered up. They can be intermittant, high, low but with no power, the gauge itself should go to the minimum.  

SOURCE: Overheated while idling in park for 5minutes.

your thermostat probably stuck closed.when you cooled it down,it opened again.change the thermostat.

SOURCE: 2004 chevy cavalier temperature gauge is all over

Check your coolant level. If you have air in the lines, the times when there's no coolant in the area of the sensor will make the temp go up rapidly, then it goes back down when coolant hits it again. You need to get the air out of the system, or you WILL have larger issues at hand, like a blown head gasket, cracked head, reduced piston ring sealing, or material transfer from the pistons to the cylinder walls. One other thing that could cause this is a faulty thermostat.

SOURCE: 2002 malibu runs hot.

Sounds like you have a faulty head gasket or maybe a cracked head.This can cause overheating and the check engine light to come on.The code for the o2 sensor is probably caused by coolant getting into the exhaust system and coating the sensor.The coolant fan may work but it cannot remove enough heat from the rad to make the engine cool off.Try some engine coolant stop leak to see if it will help.This maybe only a temperary fix.Let me know if you need more.MOE