QuestionMy 2002 XG 350 has a rough idle and every so often surges while idling. If you put it into neutral, the rpm then goes to 1500 then settles back to about 800. Every so often, the engine lacks power on acceleration but after seconds returns to normal. Any ideas?
AnswerIs your check engine lamp on? The throttle on your car is electronically controlled, and it's rare to see a problem with lack or power or poor idle without the lamp being on. If you have access to a code reader, it's a good idea to check for diagnostic trouble codes, even if the lamp isn't on.
A stuck closed EGR solenoid can cause a rough idle because it'll keep the EGR valve open when the engine is idling. This won't cause a significant lack of power, though.
I checked for technical service bulletins (TSBs) relating to your problems, and the TSB regarding the EGR solenoid was the only thing that was appropriate.
