Wierd Problem.

I'm having a really wierd Idle problem on my 93 xj 4.0L manual trans. When i start it up cold it idles high then goes down once it's warm (like it should). If I drive it as soon as it's warm it runs fine. When not in gear the idle is perfect. Once i drive it for about 5 min. though the check engine light goes one and that's when the Idle gets real wierd. If the car is in motion but not in gear it will idle high. When i come to a stop the idle goes back down after a couple of secents. It only does this after the Check Engine light goes on. I"m getting O2 sensor codes and coolant temp sensor codes. I replaced them both. Anybody ever had this problem before? any ideas?

which coolant sensor did u replace, there are two.

I replaced the coolant temperature sensor on the thermostat housing. There's another one? Where is it located? I've also replaced the temp. sensor that's on the head near the firewall.

rooster87 said:

I replaced the coolant temperature sensor on the thermostat housing. There's another one? Where is it located? I've also replaced the temp. sensor that's on the head near the firewall.

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ya thats the two, i belive the one on the head is for the puter, and the one on the tstat is dor the electric fan.