Ive got an 89 with the v6 that says its luke cold on the temp gauge even after driving it for 20 minutes. It also has a huge hesitation problem that goes away after about 10 minutes. It goes away completly if I unplug the temp sensor for the ECU. I know its heating up because the heater blows hot after only a couple of minutes idling. I just replaced the thermostat anyway because I wanted to change the coolant so Im pretty sure it wasnt that. I also tested the gauge with the grounding it out trick and it seems ok. The reason I changed the coolant was that I actually overheated the motor about 2 weeks ago. I removed the radiator cap and saw a lot of silicon strands floating in the coolant. It must have been from when I installed the new water pump this summer. I remember using a ton of silicon because I was worried that it would leak. I figured I might have gummed up the thermostat and radiator so I flushed them with cleaner. But now I think I might have got some silicon jammed up in the coolant temp sender array at the back of the motor, not alowwing it to warm up the sensors fast enough. Anyway I was just wondering if anyone else has had any simalar issues. Sorry for the long post but I just wanted to be thorough.

 

I just had this same problem with one at work. The coolant passage that comes off the housing where the temp sending unit is is plugged up. Take the little hose off and blow compressed air in both directions. The one at work was plugged where the passage goes into the water pipe that runs under the intake. That fixed my hesitation on warmup and fixed the low temp guage.

 

does it feel/hear like a misfire?? because that is what mine is doing, and I thought the mechanic had changed my temp sensor out? hmm I am pretty sure he had tried that. has anyone else had any similar problems?? mine was really bad today and it was very frustrating trying to pull in front of a car to get over into the other lane.

also I was searching around and found an ECT mod?? but I can't find any instructions for it. the link that the posts I found are broken. seem they go to one spot. so any others out there??? just need to know what to do lol. k thx