I've just finished putting on LT headers, ORY, Cutout, and a new opti with new wires. I crank it over and it runs fine until it heats up and then the car sounds like it's missing / hesitating and chugs a little right before it shuts off. When I try to start it again it runs for a few seconds and then shuts off. Only way to get it running is by pressing the gas while turning the key. But that only last a few minutes until it chugs/ hesitates and shuts off again. Only way it won't shut off is if i key my foot on the gas. I've replaced the TPS, ICM, and COIL. I've also taken apart and cleaned the IAC. There are also no codes. Anyone have any idea what it could be? Any help would be great!
Thanks

 

Coolant temp. sensor is bad.

 

To clarify, I'm talking about the one in the water pump, not the sensor in the passenger side head.

 

How would that affect the car? Just curious never herd of that failing and causing all these problems. lol

 

If you do a search on it you will find that there are many cases where it causes symptoms identical to yours.

It happened to me years ago as well. That is the sensor that communicates with the PCM. The one on the head is just for the gauge in the dash.

 

Can you tell if its bad using a data logger? If so what should I look for? I'm using freescan.

 

I'd imagine that once the car is warm the data logger would notice the change in the loop that is causing it to stall.

 

I looked at the log and didn't see any kind of crazy number for the temperature sensor.

 

When the car is warm unplug the sensor and see what it does.

 

it the coolant temp sensor, mine did the same thing. Unplug it and start it and it will probably be fine. If it is the sensor make sure the car has cooled off for awhile because water will come out and it will be HOT. Also you might want to jack up the back of the car so the water doesn't soak the opti.

 

He doesn't need to actually remove the sensor, simply unplugging it is all that needs to be done to check.

 

I know he doesnt just to check but if it is s bad sensor it does need to be replaced

 

I unhooked the sensor and the problem is still there.

 

I'm assuming it ran fine BEFORE you installed the headers, and started to run rough AFTER you installed the headers. Since it starts fine cold, and then won't run when it warms up and goes into closed loop, there's a good chance its a problem with the O2 sensors, or the wiring harness.

 

I unhooked the o2 sensors and it didn't fix the problem
UPDATE:
Now the car wont even start without my foot pressing the gas down. As soon I let my foot of it dies. Also this happens in closed and open loop. Could I have messed up installing the water pump? It almost seems like something is dragging and cutting off the engine. Any idea?