Ihave a goodman gms80903bna the furnace starts up and runs for about 4 mins and the flame goes out then comes back on after about 30 sec somethines it goes out again but i am not getting any code flashes

I have the same problem. The vent flu. Is building up condensation and running back into the furnace and cloggs the little black vent hose with water. Then it comes back on then off etc.
somehow the trick is to make as straight of an upward vent flu as possible ( definitely not 45 degree elbows and really not 60's either) seal all connections with glue.

Hello,sounds like you have a dirty flame sensor. This is a metal rod on the oppositenside of the hot surface ignitor. turn off power to the furnace and remove the flame sensor, then use steel wool and clean the flame sensor and reinstall. Next turn back power to Furnace.

adjust the gas pressure on the gas valve or replace the gas valve

Problem: Your furnace will not ignite the gas to produce heat for your home. When a furnace has a bad ignitor what I see most of the time is the following sequence of operation:

1. Thermostat calls for heat. 2. Draft inducer motor starts. 3. Pressure switch attached by a small plastic or rubber tube senses the negative pressure produced by the draft inducer and closes. 4. Draft inducer runs for 30 seconds to a minute before you hear a gas hissing sound. The ignitor did not glow, the flame sensor (a small metal probe about 1/8" in diameter, with a white porcelain base) does not sense the flame, so after 8 to 10 seconds the hissing sounds stops with no ignition of gas to heat your home. Your furnace shuts down and goes into a lock out condition until you turn your power switch back off and on again. Then the sequence starts all over again with no ignition of the gas. Solution:You probably need to purchase and install a new ignitor. I would suggest that you inspect your ignitor closely for cracks. Make sure you do not touch the ignitor with your bare hands. If you do not visually see a crack, then you could have a furnace control board problem or a limit, rollout switch problem. The furnace's control board might not be supplying the voltage to the ignitor. If your furnace lights and the gas stays on for 8 to 10 seconds, then shuts right back off, then you need to clean your flame sensor with light sand paper or steel wool. You might need a new flame sensor, but most of the time they can be cleaned an will work well after cleaning.

I cleaned the sensor that was at the the right further most burner on my Goodman and it worked. got the answer to my problem here at fixya. My burner flame only lasted 5 secs before it shut off. Thanks to all who took the time to send me a response.

Solid red typically means bad controller. Try unplugging the furnace, wait about 30 secs, then plug it back in. The possibility that the controller was sending voltage to the valve even when there was no flame is a bad sign. If the controller starts the furnace, watch it very closely and see what it does. If the solid light comes back on, it's time for a new board.

Natural gas furnace??? If so, your flame sensor switch might be bad. Once your burners ignite, they close a limit switch that lets the control module know that the gas ignited- so you don't blow gas into your house uninterrupted. Let me know if you are talking about something else.

you need the same board. the one you have is not compatible with your unit

Greg

Put water in the condensate trap