My '92 240 has started to idle up and down at stop signs and sometimes stalls when I'm not giving it gas. It's even worse when I put it in park. I found a crack in one of the air hoses and replaced it. I have also recently replaced the fuel filter and the in tank fuel sending unit. I've put techron in the tank to help clean the fuel injectors too. This has me a bit stumped at the moment. It was running pretty decent after all of the above was done. But now seems to be going back the the rough idle and stalling. No dashboard lights are on.

 

i'd A) clean the throttle body and idle air controller, and B) replace any idle air contorller hoses that are even a little hard and crunchy, and C) when reassembling, ensure the throttle position idle switch closes when the throttle is at idle, and opens almost immediately as you give it a hair of pedal.