Wierd Car Problem....(DR.Jekal/MR.Hyde) problem.

[Reno]

hey guys i had this problem since i did the tuneup with the seafoam stuff..

yes i replaced the sparkplugs o2 sensor, etc.

when my car is cold it feels like it can beat or tie a ferrari, it feels like i gots a ka-t ... but when the car gets hot or warn within 5 min.. it runs like shat..

ive searched this forum and many others but to no prevail... Sigh...

i dunno what to do ant opinions?

thx

[BadMojo]

Have you checked your coolant temperature sensor? If it's bad and your ECU thinks the engine is running cold when it's running warm, you may be running pretty rich, which would definitely lead to poor performance. I think it's definitely worth a look and the FSM has the procedure for testing the sensor.

[Reno]

okay how would i check it? and where is it located is it the thing next tot the intake mani? there are 2 things a thick yellow plug and a thin black 1 i cleaned the thick 1 with a wire brush i took a 19mm socket and wirebrushed it aswell... any ideas?

[petesleaf]

On the 240 The temp sensor is located on the front of the engine directly to the right of the upper hose to the radiator. It is also just above the thermostadt elbow hose connection. It is usually red. It is the cause of hard or failure to start when the engine is warm because when it fails the ECU thinks it is starting a cold engine thus choking it. It is often just the wires corroded were they snap into the connection. From chemical and pressure cleaning the engine. Sensors such as these pick up moisture and corrosion as resistance and usually indicate code 13 on the ECU. This is mode lll-Self Diagnostic mode. U have to unscrew the ECU( located under the passenger side below dashboard right hand kick panel) and turn it 180 degrees to view the green and red inspection lamps. Use the adjustment screw next to the lamps to get to mode lll by turning it fully clockwise with the ignition on. When the lamps flash 3 times turn the screw back. When the red lamp flashes once and the green lamp flashes 3 times it is the trouble code for 13, Engine Temperature sensor.It is easy and inexpensive to replace the sensor, which most owners do without checking the ECU Codes. Just be careful as the plastic connectors break easily.

[deviousKA]

Also this can happen if the wire connection to the temp sensor is corroded/not making proper contact. Pull the clip off the two pin temp sensor in the front of the intake manifold, clean the contacts real well and maybe bend them in a bit with a pick.