Car dies when at operating temp

[jaredmac11]

M42 starts fine but as it starts to warm up, it runs worse. It races at around 1000RPM as it warms up. When it gets to operating temp, its much worse and will die almost immediately when it drops close to or below 1000RPM.

I did some light reading and I read this is typically an ignition issue. I have Coil on Plugs... given this is a mod, it could be the way they were installed (too tall, for instance?) or it could be the coils themselves.

The spark plugs are new, the rest of the m42 is 100% new rubber and hoses.

[jaredmac11]

It was the IACV. I removed it and cleaned it, didnt resolve the issue. Found a replacement from my parts bin, cleaned that one, and all's well.

[jaredmac11]

Well I replaced the ICV with a used one but I still have the issue.

The ICV's valve moved very freely after a good so I dont believe its a bad ICV... could be wrong.

I was bleeding the coolant and noticed a moment after the Efan kicked on, the engine stared to stumble. So the thermostat opens at 88 and the temp switch starts the efan at 85. It seemed to start right when it hit operating temp.

Something tells me its not mechanical because why would it start at a pretty distinct time? It wasnt gradual, it was like a switch. Could be happenstance.

Am I mistaken and maybe my new-used ICV is bad?

[jaredmac11]

I showed the car to my buddy and he let me know the car was moving to a closed loop, hence why it ran well at open loop. Probably should have caught that. Also thinks the ICV I used is still bad. So if anyone has one...