I need help! As most DIY I know enough to be dangerous so I need real help. This is my Moms car. It all started when it cut off all the sudden and wouldn’t restart while idling at a traffic light. I discovered that it was overheated. In fact completely out of water because of a hole in the reservoir. When it cooled down and restarted it was obvious there was a blown head gasket. Plumes of white smoke from the exhaust, pressure up through the reservoir and water in the oil. Because it’s a 2002 my son and I decided to attempt to fix it on our own instead of scraping it. It has been a great car for her. She is 73 and doesn’t have the money to just go buy a new one. So we put on new head gaskets but didn’t get the heads checked. (I know that was probably dumb but I was willing to take a chance). During the HG install I broke the DFE sensor and hose. I also found someone before us had cut the EGR Pipe! So I replaced both of those. The EGR looked burnt and clogged so I replaced it. After the head gasket install the car starts fine now but the idle was up and down and would cut off eventually. Found a vacum leak at the PVC hose. Replaced it and pvc valve. Found a second vacum leak on the back of the plastic plenum. Replaced that hose too. It ran better but still having the same issue. I replaced the IAC sensor. Again better but still runs really rough at idle. It threw a P1506 code which I read could be caused by air leak in plenum. I didn’t have an inch pounds torque wrench on the original install so I took the plastic plenum back off, rented an inch lbs torgue wrench and reinstalled. The code went away but idle still rough. Spark plugs were changed when HG was. Wires only have around 2500 miles on them. I’ve cleaned the Mass Air sensor with the proper cleaner. I’ve sprayed starting fluid around all the air and vacum connections without any change. It runs great once it gets past idle. As it warms to operating temperature the idle gets even worse. Oh yeah I even took the manifold loose to see if the catalytic converter could be stopped up since it had antifreeze ran through it during the HG issue. I’m at a loss! The mass air flow sensor is over 100 bucks. I don’t mind changing it but I hate to add another 100 to an already sinking ship without at least knowing it could be the problem. Any suggestions or ideas will be greatly appreciated. I realize I’m too deep into it already so please don’t just say dump it. Even if we buy her a newer car I’d like to give this one to someone who can use it running correctly. Thanks in advance for your help.