ok i got a 1992 mustang four cylinder did the whole v8 swap now im putting efi stuff in it from a 1993 mustang. i cant get it to idle right it surges and i dont know whats causing it i pulled the codes and got 81 82 and 85. i could only guess thats it 82 and 81 because thats the vacuum bypass stuff and i only have one but i dont see a plug for another and i dont know if thats evene the problem with it. i dont have cats on it or a smog pump capped the holes off in the back of the head but it still has the egr valve. i just put brand new o2 sensors in it. it does have exhaust leaks before the o2 sensors but i dont see how a leak is going to let fresh air in when its pushing air out or if itd even have anything to do with the surging idle. would getting dummy o2 sensors be a good idea? also i put a brand new iac mass air and tps on it i did delete the egr by putting a plate over it did nothing so i put the egr back on. after all the the idle surging still remains. could it be from the ect causing idle surging or what would your oppinions on this be? does anyone know if i need the vacuum diverter solieniod if i dont have a egr valve or if i do can some show me or inform me about that and where all the vacuum lines go incase i dont have them going to the right place or if anything lik that could cause it. im sure i dont have any vacuum leaks but i dont know what it could be o2 sensors others things i have know clue please help i just cant seem to figure this out

 

Fix your exhaust leaks.

 

Make sure all grounds wires are in place

 

The leaks in the exhaust will pull air into the exhaust due to the scavenging of the h pipe , Get your leaks fixed ....