You didn't mention how many miles are on the car but I assume it's more then 50K.
Lets start with the basics.
1) Since you are getting an EGR code you need to check to see if the valve is stuck open.
2) Since you removed and cleaned the intake you need to inspect the plug wires and coil pack for damage. Also all of the electrical and vacuum connections need to be checked.
3) Next check the IAC valve for proper operation.
4) Check the plugs for damage/ware.
5) Get the fuel injectors cleaned by someone with the proper equipment. The stuff you poor in you tank is good for maintenance at best. The only way to clean injectors is to
connect directly to the fuel rail with a nasty blend of solvents not available at your local auto parts store.
6) Do a base engine check Vacuum/compression.
hope this helps
jeff
