I have an 89 formula 350 and when i get low on gas the SES light will come on and the rpms will drop real low and almost stall. Does anyone know whats going on with it. I try and get the codes but i guess the light has to stay on to get them. Also i used to get code 15 and 12. Does that have anything to do with it? Thanks.
Scott

So the engine boggs under acceleration? Sounds like your catalytic convertor could be clogged or you could have a bad o2 sensor. Does it idle OK?

It bogs while its coasting down or with very little throttle. It idles pretty low at 550 rpms. i had a code for the TPS and another for the coolant sensor. Could either one of those cause it?

They both could. I would set the TPS. It's easy to do. Search this board for the article. The CTS could do this too, the ECM uses the info it gets from the CTS and sets the timing accordingly. Timing has a big factor on idle and throttle response.

I'm thinking its the coolant temp sensor because the fan is always on. It never turns off. Also i dont have a way to check the TPS.