My car is back firing and wont stay on. Rebuilt tbi, what can my problem be?

Won't idle -check the idle air control valve, TPS and MAP sensors and to include fuel pressure check-

Just to add to this one what did you replace when you rebuilt the tbi?Did you replace the vacuum plate?How are the vacuum lines on the vacuum plate they rot out from the heat and over time. Also the how is the hose going to the pcv?They split and rot out also. ALso I would check the coolant temp sensor and connector Its the bottom sensor with two wires going to it a black one and yellow one. Have you checked the plugs to see if you fowled them?ALso what kind of plugs do you have?There not platnuim plugs I hope?ALso do you have any codes in the computer?

I would be more worried about bent valves or bent connecting rod from pouring that sea foam in the tbi then a plugged cat.I would do a compression test and let me know the readings of all the cylinders. Also what kind of plugs did you put in?You need to also check all the things I mention. Including fuel pressure and spark.

There regular plugs there not platnuims?Because the platnuim plugs carbon foul in those engines. To do a compression test you remove all the spark plugs get a compression tester screw the hose in where the spark plug would go. Also you need to remove the eis and inj fuses. Then hold the gas pedal all to the floor the crank the engine over 10 revolutions with the starter. Before you do that did you check for codes?