CarpenterWagon

I have a 1990 302 aod and on cold start up smoke comes out from behind the intake, in the bell housing area. I also noticed it come in through the heat vents. It only smokes for a few seconds then stops. If I restart, it doesnt do it. Any ideas?

dirtcrew51m

Probably a leaky cross over tube or an A.I.R pipe blowing off moisture until they warm up.

CarpenterWagon

A.I.R? Cross over what?

dirtcrew51m

They are basically th same things, those small tubes and hoses on the motor that are used to recirculate exhaust gas, there is a round thing that has a rubber hose connected to it and screws onto a pipe on the pass side, its a check valve, they rot out alot check that.

CarpenterWagon

I've got another question. If the truck gives off no codes can I asume all the sensors and parts are in working order?

dirtcrew51m

Yes, there are also sensors that post no codes when bad, such as a tfi, pip, a leaky or broken sensor or part will not always give off a code.