I've got a 99 454 MPI, that I've been have a few problems. It starts & idles fine. As it warms & I run it up to about 2000 rpms, it starts loading up & trying to stall, basically running rich. I found that my regulator was bad, replaced it, it did help, but not with the rich condition. Yesterday, I removed my MAT Sensor, & ohm'd it out. It is open, no resistance at all. I then put a heat gun on it to warm it up, no change. So, it definetly appears to be bad, but my question is, will this cause the rich condition? I'm thinking it will, I'm just looking for a second opinion from folks much more advance than myself.

Yes, a bad IAT can affect the way the engine runs. You can purchase a resistor and temporarily put it in place of the IAT to see if your probelm clears up. A 1.8k resistor will simulate 100 degree intake air temp.

Dave

I'ts probably your CTS sensor (coolant temp sensor).

Thanks for the input, I had wondered if I could simulate the proper temp. I assume I should be able to get the resistor from Radio Shack, or any other electronic supply, I do that tomorrow.
As for the CTS, I have it removed, & I do believe I am going to change it, considering the price is only about $25, I don't think I can go wrong with a new one.

Put a scan tool on and check the codes.

Dave, Thanks for the tip, I think that had to be the cheapest "test" tool I've ever bought, .99...& it worked great. I simply plugged it in & the fired the boat up, it ran perfect, just like it should. I ordered the IAT switch, & it will be here tomorrow or Thurs. Thanks again

Is there 2 temp. sensors on 95 350 mpi one for the ECM and one for the gauge on dash? Because mine is doing the same thing running very rich and barly idles. Any input