Post throttle body cleaning and loss of heater core... cel

[ron23]

2003 galant es (i believe). 2.4 148000 miles

Ok. Quick question and then long explanation. I am facing the firewall looking in back of the engine and under the throttle body. There is a hole which takes in air it is about the diameter of a quarter. It looks like it takes 1 small screw/bolt at about 7 o'clock position. At about 2 o'clock there is a (brass?) plug about 3mm. Does anyone have any idea what goes in the hole? The next morning the car would start and immediately stall unless my foot was on the gas pedal. I could drive the car, but I could never take my foot off the gas without stalling. I also noted a wheezing sound, obviously some type of air movement into or out of engine area. I covered this hole and the car would run fine without the wheezing sound, but after 10 minutes or so got a cel.

Longer explanation. Car would lose rpms when I mashed the gas.. run at a higher temp and the heater blew cold air...did not give off code. Ran blue devil to seal heater core. Cleaned out throttle body. Car ran for an hour accelerated properly when given gas. Tried to start car next day and got the situation explained above where I could not keep the car started or running without having my foot on the gas. Car coded 1400 differential pressure sensor I think. Corked the hole under the manifold pressure sensor and throttle body and drove for about 10 minutes or so and the CEL came on. Coded 0421 and 507.
507 Large vacuum seal leak; dirty throttle body; faulty IAC valve/throttle body... 0421 Faulty catalytic convertor; exhaust leak near rear O2 sensor; Faulty rear O2 sensor.

What is this hole I covered and where do I go from here... I just ebayed a differential sensor. Also before a few days ago I had never had a CEL or any problems with these systems. Thank You.

[coconut]

I have a throttle body laying around somewhere. Let me look at it and see if your missing something. Can you post a picture of the area you are talking about?

[ron23]

I have a throttle body laying around somewhere. Let me look at it and see if your missing something. Can you post a picture of the area you are talking about?

Thank you, but I don't have a photobucket account. I realized after the throttle body is different than the oem. I found out the hole is just supposed to be covered up. I filled it with a penny and some hardening putty.

[coconut]

Good to hear you figured it out.

[ron23]

Good to hear you figured it out.

This one may be a to be continued situation. .. swapped out pcv valve for a new one, swapped IAC with a used.. but Idled at 2000 rpm.. cleaned my IAC.. drove again today.. CEL and some hesitations when hitting the gas also some random knocking.