I have an 04 xg350l. Car has about 175000 miles on it. It was running rough when i bought it so i changed the plugs, wires, coils, all o2 sensors, ect. Problem im having now is when i have the EGR valve hooked up ot runs really rough. Unplug it it runs fine. Changed the EGR and no change. Now once it runs for about 5 mins and turn it off its really hard to start. Im new to hyundai and have little experience with them. Anyone else have this problem? If so what fixed it and any other sugestions? Ive dumped about a grand into the car trying to figure it out replacing part by part.

 

You can try:

*Check you vacuum connections/setup. There is a schematic/picture under the hood (or send me a couple photos)
*Change the EGR solenoid.
*Injectors (try cleaner in fuel tank a couple times)


ANY FAULT CODES? CHECK LIGHT?