Rough idle

2012 VOLKSWAGEN GTI
104,000 MILES • 2.0L • 4 CYL • TURBO • 2WD • MANUAL
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SHANE GRIMSON
  • MEMBER
  • 1 POST
Had an IAC problem. I changed throttle body then had a misfire in cylinder two. changed all spark plugs then had a misfire in two still. then switch coils two and three and misfire followed. change onion coil on three and then had a misfire in one, three and four. redid throttle body and misfires went away. now I have a rough idle and rpm's spike from 650 almost stalling to 1500 and at idle. what else could be wrong? I do not think I have a vacuum leak and engine does shake like if there were a misfire. suggestions?
Sep 7, 2017 at 8:21 AM
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STEVE W.
  • ✓ASE Certified Mechanic
  • 15,200 POSTS
  • ASE Certified Mechanic
I would check for a vacuum leak, even if you are sure there is not one as they are very picky about that. Check the PCV for proper operation and it would not hurt to do a top cylinder cleaning to remove any extra carbon that VW's are known for.
Sep 7, 2017 at 8:50 PM
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