Coolant temperature sensor pegged over 260?

Hi,

It shouldn't need more than a few short trips. Since you had the throttle body off, are you sure there are no engine vacuum leaks? That will cause it to not idle.

Here is a link that shows how to check for engine vacuum leaks:

https://www.2carpros.com/articles/how-to-use-an-engine-vacuum-gauge

Let me know.

Joe

Yes, no vacuum leaks repair all that was found with brake cleaner. That's what I thought too, as I was looking online and found no actual answer but figured I'd ask someone on here, but it has been a lot of trips long and short. IAC valve been cleaned etc. But would it matter that I unplugged the ECM and it deleted all fuel trim codes and whatever else ECM holds like I don't have the power it used to have before hand. Do y9ou know what would cause a high RPM misfire, causing it chug?

As far as disconnecting the ECM, it will relearn everything within a few miles. If you have taken trips, that information should be saved again.

Now, a loss of power, high RPMs, and chugging can be a few things. Have you checked fuel pressure? If it is off (too high or low) it can cause this. Is there any smoke from the exhaust? Have you scanned for codes now? Does the exhaust have an odd smell or sound to it?

Let me know.

Joe

Without doing a idle relearn procedure? Does Pontiac have one for the lg8 engine? But yes ran codes and the only one that's came up since I unhooked the ECM, was idle to low, looked it up online and just said to do idle relearn. Probably did 5 or 6 different ones different cars. But no I haven't checked fuel pressure I will do that tomorrow when I have light. No smoke at start up or when hard acceleration, I bought the car maybe year ago and 3 months after had to replace the catalytic converter due to being clogged, it doesn't feel like that. Also replaced fuel filter honestly not super long ago with miles or time but could it be plugged again? What should fuel pressure be at idle and do I test it with RPMs up to?

Hi,

On this vehicle, the IAC (relearn) should be done automatically by the PCM by simply turning the key to the run position and then off. See pic 1 below.

The remaining pics are diagnostic for the IAC. Take a look through them to see if they help.

As far as fuel pressure, the last pic below shows the manufacturer's specs. Here is a link that explains in general how to check the pressure:

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

Let me know what you find or if you have other questions. Also, let me know the specific code you are getting.

Take care,

Joe

See pics below.