P1130-01' S 61k
 

On a road trip the other day,the CEL came on(solid),gave code P1130. Drives fine.

As soon as I remove the oil filler cap,the idle gets funky,any ideas?

P1130 means cyl. #4-6 is running lean @ RPM close to idle, so you might have a small vacum leak maybe thru the AOS.

Any time you remove the oil cap while the engine running it will cause the engine to run rough and maybe blue smoke from the exhaust. I other words do not remove cap while engine is running.

...I've removed the oil cap plenty of times when changing the oil with the car running after initial fill up to add more as needed...it never had a funky idle when the cap was removed.

Just got word from the shop....MAF was bad....made no sense they said because normally the when the MAF goes it creates CEL codes indicating both side are either rich or lean...not just one side.

Which may tell you
 

that the O2 sensors are giving different readings and that would explain how one side gives the readings before the other.

I know one side of my car at about 55K miles had a tired O2 sensor I detected via my code reader. I changed that one and had no codes, not even pending codes, on the other side. Eventually changed the other side a year later even though it never showed a problem via a CEL or pending codes.

My suggestion is to frequently monitor your codes via the OBDII port and a code reader just in case this is the same with your car.